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Aerial view of River Severn floodwater across fields near Tewkesbury, downstream of the Severn Stoke flood scheme.

Severn Stoke Flood Scheme: How the £5.25m Flood Bank Works

The Severn Stoke flood scheme is a 700m earth flood bank built along the western edge of Severn Stoke, a Worcestershire village on the River Severn between Worcester and Upton-upon-Severn. The Environment Agency and Worcestershire County Council confirmed it fully…
Posted on 10th November, 2026
by Edward Bouët
Cutaway of soakaway crates wrapped in geotextile, filling with rainwater from an inlet pipe and infiltrating into the surrounding soil.

Soakaway Crates: How They Work and When They’re Allowed

Soakaway crates are modular plastic boxes, wrapped in a geotextile and buried, that hold rainwater from roofs and paving and let it soak into the surrounding ground. Each box is mostly empty space, so a few of them store far…
Posted on 9th November, 2026
by Antony Rousou
Newly planted rain garden between a road and a pavement in Brighton, with a cobbled area at the near end of the bed.

What Is a Rain Garden? How Rain Gardens Manage Surface Water

A rain garden is a shallow planted hollow that collects runoff from a roof, path or road, holds it for a few hours and then lets it soak into the ground or drain away slowly, filtering out pollutants on the…
Posted on 6th November, 2026
by Antony Rousou
French drain under construction, with a geotextile-lined trench, clean stone and perforated pipe ready to lay.

What Is a French Drain? How It Works and When It Isn’t Enough

A French drain is a gravel-filled trench, usually with a perforated pipe in the bottom, that collects water from the surrounding ground and carries it away by gravity. It is one of the simplest fixes for a waterlogged lawn, a…
Posted on 5th November, 2026
by Edward Bouët
Vacuum hose clearing silt from a road gully with its grate lifted, the same emptying a silt trap needs.

Silt Traps and Catchpits: How They Work and When You Need One

A silt trap is a small chamber in a surface water drainage run that slows the flow down so grit, soil and debris settle into a sump before the water moves on to a soakaway, crate tank, pond or sewer.…
Posted on 4th November, 2026
by Edward Bouët
River Medway at Tonbridge in high flow, downstream of the Leigh flood storage area that holds back the flood peak.

Leigh Flood Storage Area: How the Barrier Works and What the 2026 Expansion Changed

The Leigh flood storage area is the Environment Agency's flood barrier and reservoir on the River Medway, between Leigh and Penshurst, a few kilometres upstream of Tonbridge. In a flood its gates close, the peak of the river is held…
Posted on 3rd November, 2026
by Antony Rousou
Heavy rain falling over a lake and mountain valley, the kind of rainfall the flood estimation handbook is used to estimate.

Flood Estimation Handbook (FEH): What It Is and How It Works

The Flood Estimation Handbook (FEH) is the UK's standard method for working out how big a flood or a rainstorm of a given rarity will be at a particular place. Give it a location and a probability, such as the…
Posted on 30th October, 2026
by Antony Rousou
Gloved hand collecting a water sample from a water body for quality testing under the Water Framework Directive.

What Is the Water Framework Directive? The UK Rules Explained

The Water Framework Directive is the law that sets the standard every river, lake, estuary, coastal water and aquifer in England and Wales is judged against. It does two things. It stops any water body getting worse, and it requires…
Posted on 27th October, 2026
by Jackie Stone
Manning's equation chalked on a blackboard beside Q = AV, the hydraulic radius formula and a trapezoidal channel sketch.

Manning’s Equation and Manning’s n: How Roughness Shapes Flood Levels and Drainage

Manning's equation estimates how fast water flows, and how much of it a channel or part-full pipe can carry, from three things: the shape of the cross-section, the slope, and a roughness value known as Manning's n. In SI units…
Posted on 26th October, 2026
by Edward Bouët
Water diverted by the Dujiangyan irrigation system running through the town at dusk, split around a mid-river island.

Flood control without gates: how the Dujiangyan irrigation system has worked for 2,280 years

The Dujiangyan irrigation system is a flood control and irrigation scheme on the Min River in Sichuan that has been running since the third century BC, and it does its job without a dam across the river, without stored head,…
Posted on 23rd October, 2026
by Edward Bouët
Cottage close to the edge of the eroding chalk cliff at Birling Gap, East Sussex, where coastal erosion is nearing homes.

Coastal Erosion in the UK: How It Happens and What It Means for Property

Coastal erosion is the permanent loss of land to the sea. On the soft clay and sand cliffs of eastern and southern England, waves cut away the foot of the cliff and the face above collapses. The cliff top moves…
Posted on 22nd October, 2026
by Edward Bouët
Storm surge floodwater washing past a row of beach huts on a low-lying stretch of coast.

What Is a Storm Surge? How Surges Form and Flood the UK Coast

A storm surge is a rise in sea level above the predicted tide, caused by wind and low air pressure during a storm. UK news reports often call it a tidal surge. It is the same thing: the extra water…
Posted on 21st October, 2026
by Edward Bouët
Aerial view of Bridgwater Tidal Barrier construction on the River Parrett, with cranes and steel cofferdams across the channel.

Bridgwater Tidal Barrier: How It Works, What It Costs and When It Opens

The Bridgwater Tidal Barrier is a flood barrier being built across the River Parrett near Express Park in Bridgwater, Somerset, by the Environment Agency and Somerset Council. When an exceptional tide is forecast, two 15-metre vertical lift gates will close…
Posted on 20th October, 2026
by Antony Rousou
View through a concrete pipe culvert barrel towards its outlet and the stream beyond, showing what is a culvert from inside.

What Is a Culvert? Culverts, Ownership and Consent in the UK

A culvert is a covered channel or pipe that carries a stream, ditch or other watercourse under a road, a railway, a driveway or a building. Ask what is a culvert in the UK and the answer runs from a…
Posted on 19th October, 2026
by Edward Bouët
Clay sewer pipe on gravel bedding in a shored trench beside a concrete manhole ring, the kind of pipe a build over agreement protects.

Build Over Agreements: What They Are and When You Need One

A build over agreement is the water company's written consent to build over, or within 3 metres of, a public sewer it owns. You need one before an extension, conservatory, garage or outbuilding goes over or close to a sewer…
Posted on 16th October, 2026
by Antony Rousou
Aerial view of Arundel and the tidal River Arun in Arun district, whose council requires a Lidsey Drainage Impact Assessment.

Lidsey Drainage Impact Assessment: What Arun Requires and Why

A Lidsey Drainage Impact Assessment is a statement Arun District Council requires with every planning application in the catchment of Lidsey Wastewater Treatment Works. It explains how foul water and surface water will leave the site, and how the development…
Posted on 15th October, 2026
by Ellen Webb
Flooded red-brick homes on a UK residential street, showing why flood risk and the UK housing market are linked.

Could UK Homes Become Uninsurable? Flood Risk and the Housing Market

Uninsurable homes are a real but limited prospect in the UK: most homes will keep flood cover, and the change will come gradually rather than overnight. About 6.3 million properties in England sit in areas at risk of flooding, according…
Posted on 14th October, 2026
by Jackie Stone
Environment Agency Flood Action graphic for Flood Action Week, with cars and a black cab driving through a flooded city street.

Flood Action Week 2026: what it is, when it runs and whether it works

Flood Action Week 2026 runs from 12 to 18 October 2026. It is the Environment Agency's annual public awareness campaign, asking households and businesses across England to check their flood risk, sign up for warnings and make a plan before…
Posted on 12th October, 2026
by Jackie Stone
Bus spraying surface water flooding on a London street, the type of event the Flood and Drought Resilience Taskforce covers.

Flood and Drought Resilience Taskforce: What Is Actually New?

The Flood and Drought Resilience Taskforce is a government advisory group, chaired by Floods and Drought Minister Emma Hardy, which met for the first time on Wednesday 14 October. Defra announced it on 11 October as a new body. On…
Posted on 11th October, 2026
by Edward Bouët
Drone view of the River Severn flooding houses at Ironbridge, where flood defences for homes face a different depth at each house.

Home Flood Defences: Doors, Barriers, Airbricks and What Comes First

Flood defences for homes are the products and building changes that stop floodwater getting into a house, or limit the damage when it does: flood doors and door barriers, self-closing airbricks, non-return valves on drains, sealed walls, and a sump…
Posted on 9th October, 2026
by Jackie Stone
Thames river wall opposite the Palace of Westminster, one of the tidal flood walls that line the river through central London.

What Is a Flood Wall? Design, Failure and Building One Around a House

A flood wall is a permanent, vertical barrier that holds floodwater back from the land behind it. Flood walls are built in brick, masonry, reinforced concrete or steel sheet piling, usually along a riverbank or seafront where there is no…
Posted on 7th October, 2026
by Antony Rousou
Demountable flood barriers braced along a riverside street, holding back a river in flood with seepage pooling behind them.

Temporary and Demountable Flood Barriers: How They Work, and Why Warning Time Decides

Temporary flood barriers are free-standing units brought to a site and put up when a flood is forecast. Demountable flood barriers slot into foundations, sockets or channels that stay in the ground all year. Both are active defences, which means…
Posted on 6th October, 2026
by Jesy Ferry
Storm waves breaking against the stone sea wall at Dawlish in Devon, part of the sea defences along the town's seafront.

Sea Defences: How Sea Walls, Groynes, Rock Armour and Beach Nourishment Work

Sea defences are the structures and managed natural features that stop the sea flooding or eroding the land behind them. They fall into two families: hard defences such as sea walls, rock armour, revetments, groynes and offshore breakwaters, which resist…
Posted on 5th October, 2026
by Emma Jeffery
Rain falling over dense low-rise housing on the flat floor of the basin, the ground at the centre of the Mexico City sinking.

Why Mexico City is sinking: the lake it drained, and the ground that followed

Mexico City is sinking, and the cause is neither climate change nor bad luck. The ground is falling because water was taken out from underneath it, and the fine grains of an old lakebed have been repacking themselves ever since.…
Posted on 2nd October, 2026
by Edward Bouët
Aerial view of hard coastal flood defences: a concrete sea wall and promenade along the foot of a chalk cliff below a coast road.

Types of Flood Defences: How Flood Defences Work in the UK

Flood defences are the structures and measures that keep floodwater away from people and property, or limit the damage when it gets in. The types of flood defences in use in the UK run from a tidal barrier protecting a…
Posted on 1st October, 2026
by Edward Bouët
Public sewer map extract from Thames Water showing foul and surface water sewers, manholes, pipe sizes and flow arrows along a street.

Public Sewer Maps: How to Find Sewers Near a Property

A public sewer map is the water company's record of the sewers, lateral drains and disposal mains it owns. Every sewerage company in England and Wales has to keep one under section 199 of the Water Industry Act 1991 and…
Posted on 30th September, 2026
by Antony Rousou
Gauge board in muddy, fast-flowing river water, a stage reading that needs converting before it can be compared with a level above Ordnance Datum.

What Does AOD Mean? Above Ordnance Datum, mAOD and Floor Levels Explained

AOD stands for above Ordnance Datum, the national zero that heights in Great Britain are measured from. A level written as 12.40 mAOD sits 12.40 metres above that zero, which is fixed at mean sea level recorded at Newlyn in…
Posted on 29th September, 2026
by Kacper Buksa
What is a weir: the River Avon spilling over the stepped, curved crests of Pulteney Weir below Pulteney Bridge in Bath.

What Is a Weir? How Weirs and Sluices Control River Levels

What is a weir? It is a low barrier built across the full width of a river, so that the water spills over its top instead of passing round it. The job of a weir is to hold the river…
Posted on 28th September, 2026
by Emma Jeffery
Low masonry weir spilling into a pool on an upland stream, the hold-and-release principle behind a tank cascade system.

A silt trap, a reed bed and a strip of scrub: Sri Lanka’s 2,000-year-old tank cascade system

A tank cascade system is a chain of small reservoirs built down a shallow valley in Sri Lanka's dry zone, so that the spill and seepage from each one becomes the inflow to the next. Thousands of them survive, and…
Posted on 26th September, 2026
by Edward Bouët
Natural England logo over misty rooftops at dawn, for an article on Natural England SSSI consultation in planning.

Natural England and SSSIs: What It Means for a Planning Application

A planning application near a Site of Special Scientific Interest (SSSI) can be referred to Natural England, the government body that protects England's SSSIs. Natural England advises the council on whether the scheme could harm the site. It formally objects…
Posted on 25th September, 2026
by Edward Bouët
River in flood across its floodplain, covering allotments beside a railway, the kind of event that can lead to managed retreat.

Managed Retreat: When Homes Are Moved Away From Flood Risk

Managed retreat is the planned removal of homes, people and infrastructure from land where the risk of flooding or erosion can no longer be managed at an acceptable cost. The buildings are bought, then demolished, and the land goes back…
Posted on 24th September, 2026
by Jackie Stone
Floodwater standing across a village lane beside brick cottages and a pub, the kind of ground Flood Zone 3b covers.

Flood Zone 3b Explained: The Functional Floodplain in England

Flood Zone 3b is the functional floodplain: land where water from rivers or the sea has to flow or be stored in times of flood. It is the most heavily restricted flood zone in the English planning system, and the…
Posted on 23rd September, 2026
by Emma Jeffery
Bulk earthworks regrading a greenfield housing site, the work behind any attempt to raise land out of the floodplain.

Can I Raise My Land to Get Out of the Floodplain?

Raising the ground is one of the first ideas people reach for when a site turns out to sit in Flood Zone 2 or 3. The answer is almost always no. You cannot raise land out of the floodplain in…
Posted on 22nd September, 2026
by Edward Bouët
Shallow spring-fed flow across grassland, the kind of seepage perched groundwater produces where a clay layer daylights.

Perched Groundwater: How to Tell It From the Water Table

Perched groundwater is a body of shallow groundwater held above the main water table by a layer of low-permeability ground, with unsaturated material beneath it. That unsaturated gap is the definition. Water standing in a trial pit on a clay…
Posted on 21st September, 2026
by Jackie Stone
Japanese river with one bank left as open floodplain and the other hard-engineered, the same choice an open levee makes.

Kasumi-tei: how Japan built levees with gaps in them on purpose, and why it stopped

An open levee is a flood embankment built in overlapping segments with deliberate gaps left between them, so floodwater can spread sideways onto farmland as the river rises and drain back out through the same gaps as it falls. Japan…
Posted on 18th September, 2026
by Edward Bouët
Coloured land parcel classification draped over LiDAR relief, a figure built from source data rather than a MAGIC map extract.

The MAGIC Map Explained: What It Shows, and What It Doesn’t

The MAGIC map is Defra's free public map of environmental and countryside data for Great Britain, holding more than 400 layers from around 30 organisations in a single browser-based viewer. For anyone appraising a development site it answers one narrow…
Posted on 17th September, 2026
by Kacper Buksa
Old cast-iron hand pump, the kind of private water supply that carries a groundwater source protection zone with no mapped extent.

Groundwater Source Protection Zones: What They Are and What They Change

A groundwater source protection zone is an area the Environment Agency draws around a groundwater drinking water abstraction to show how quickly a pollutant released at that point would reach the supply. There are over 2,600 of them in England.…
Posted on 16th September, 2026
by Jackie Stone
Country lane and hedge line beside a ploughed arable field, a typical boundary for land drains on a development site.

Land drains on a development site: what to do when you find them

Land drains on a development site are not an obstruction to be cleared. They are somebody's drainage, they may carry water from well beyond the red line, and cutting one without a plan is the shortest route to a neighbour's…
Posted on 15th September, 2026
by Edward Bouët
Terraced stone footings under excavation at Liman Tepe, Urla, the site that reopened the question of the oldest drainage system in the world.

The oldest drainage system in the world: who actually has the claim

A stone drainage system roughly 5,000 years old was reported at Liman Tepe on the Turkish Aegean coast on 14 September 2026, and the coverage reached, as it usually does, for the superlative. It should not have. There is no…
Posted on 14th September, 2026
by Edward Bouët
A steel footbridge over a river in spate, in the kind of steep catchment that Machu Picchu drainage discharges to.

129 drains and half a metre of loam: how Machu Picchu handles two metres of rain a year

Machu Picchu takes close to two metres of rain a year on a granite ridge that falls away at roughly 50% either side, and it has stood there for around six centuries. The photograph everybody knows is the part above…
Posted on 11th September, 2026
by Antony Rousou
Contractor cutting orange PVC-U pipe on a housing site, where sewers for adoption are built to a fixed specification.

Whatever happened to Sewers for Adoption?

Sewers for Adoption was the design guide that told developers how to build a sewer a water company would take over. It stopped doing that job in England on 1 April 2020, when Ofwat's Code for Adoption Agreements came into…
Posted on 10th September, 2026
by Antony Rousou
Concrete dam releasing water through its scour valves, the kind of raised structure breach modelling data is prepared for.

Why is dam breach data a secret?

Ask a navigation authority or a reservoir undertaker for the breach modelling data behind a raised embankment above your site, and there is a fair chance you will be told that the information is held and will not be released.…
Posted on 9th September, 2026
by Jesy Ferry
Jousting re-enactment at a castle, the kind of site where medieval drainage had to serve a large working household.

Medieval drainage: the moats, monks and great drains you can still go and see

Medieval drainage has a public-relations problem. The popular picture is a filthy street, a chamber pot tipped out of a window and a moat brimming with sewage. A thousand years of squalor, sitting neatly between the Romans and the Victorians.…
Posted on 8th September, 2026
by Edward Bouët
Do you need planning permission for a swimming pool: aerial view of a new garden pool with drainage pipes and an open trench alongside.

Do You Need Planning Permission for a Swimming Pool?

Most people asking whether you need planning permission for a swimming pool get the same answer everywhere they look: probably not. That answer is usually right, and it is also the less useful half of the question. Permission settles whether…
Posted on 7th September, 2026
by Jackie Stone
Dry island flood risk from the air: farm buildings on ground still clear of the water, with the access road and fields submerged.

Dry Island Sites: The Flood Risk Problem Outside the Flood Zones

A dry island is a piece of land that does not flood, surrounded by land that does. The site stays dry; everything around it goes under. Dry island flood risk is what follows from that position: occupants cannot leave, emergency…
Posted on 4th September, 2026
by Jackie Stone
Grid-scale battery storage compound and its own substation seen from the air, the site type a BESS flood risk assessment covers.

BESS Flood Risk Assessment: What a Battery Storage Application Needs

A BESS flood risk assessment is the site-specific report a battery energy storage scheme submits with its planning application, and since 17 August 2026 it has been a harder document to write. Annex F of the August 2026 National Planning…
Posted on 3rd September, 2026
by Jesy Ferry
Aerial view of foam and discoloured water in the surf beside coastal groynes, the coastal setting where dry weather flow limits apply.

Dry Weather Flow: What a Dry Day Spill Tells You About Sewer Capacity

Dry weather flow is the average daily volume reaching a wastewater treatment works when it has not been raining, and it is the number every foul drainage decision in a constrained catchment eventually rests on. When a storm overflow discharges…
Posted on 2nd September, 2026
by Jackie Stone
Sediment-laden debris flow sweeping through Gyirong Port at 10:59 on 26 August 2026, the surge often misreported as a glacial lake outburst flood.

Glacier Collapse, Not a Glacial Lake Outburst Flood: What Happened in Nepal

At 08:37 on 26 August 2026, a mountainside in the Langtang Himal gave way. Seven minutes later a wall of rock, ice and liquefied sediment crossed the Nepal-China border twenty-two kilometres away, moving at close to 190 kilometres an hour.…
Posted on 2nd September, 2026
by Edward Bouët
Black plastic soil and waste pipework running between timber floor joists, the sanitary pipework BS EN 12056 covers.

BS EN 12056 explained: the standard for drainage inside buildings

BS EN 12056 is the British and European standard for gravity drainage inside buildings. It covers everything from the trap under a washbasin to the gutter on the roof, and it stops at the point where wastewater leaves the building.…
Posted on 1st September, 2026
by Edward Bouët
Large data centre campus with plant-covered roofs beside open water, the setting a data centre flood risk assessment has to address.

Flood Risk and Drainage for Data Centre Planning Applications

A data centre flood risk assessment has to clear a higher bar than the industrial-shed template most schemes were still using a year ago. Since 17 August 2026 the National Planning Policy Framework has listed data centres as essential infrastructure.…
Posted on 28th August, 2026
by Edward Bouët
Rivers and sea flood depth data on the Defra Data Services Platform, showing the seven depth bands.

Flood Depth Data for Rivers and Sea: A Practitioner’s Guide

On 27th August 2026 the Environment Agency published flood depth data for rivers and the sea. Four datasets appeared on the Defra Data Services Platform covering present-day and climate change scenarios, defended and undefended, with no announcement, no press notice,…
Posted on 27th August, 2026
by Freya Pott
Horse cantering in an outdoor ménage on an equestrian holding, where planning permission for stables and arenas is usually required.

Equestrian flood risk and drainage: the planning rules for stables, field shelters and ménages

Planning permission for stables is needed far more often than owners expect, and the flood risk and drainage requirements that come with it are the part almost nobody writes about. Horses are kept on low-lying grazing land: the cheap, wet,…
Posted on 27th August, 2026
by Jackie Stone
Aerial view of an outdoor electrical substation compound and its fenced perimeter, the subject of a substation flood risk assessment.

Flood Risk Assessments for Electrical Substations

A substation flood risk assessment establishes whether a proposed electrical substation will be reached by flooding during its working life, and sets the levels and the protection the equipment needs to survive it. It can be required for planning. It…
Posted on 27th August, 2026
by Jesy Ferry
Sunken lightwell and below-ground window on a stone terrace, the entry route a basement conversion flood risk assessment must address.

Basement and Cellar Conversions in a Flood Zone: The 2026 Planning Rules

A basement conversion flood risk assessment has to answer a question no other householder application faces: what happens to the people in the lowest room when the water arrives. Below-ground space is the only part of a home where the…
Posted on 26th August, 2026
by Edward Bouët
Newly built replacement dwelling on an existing plot, the type of scheme that follows a decision to rebuild a house in a flood zone.

Can You Knock Down and Rebuild a House in a Flood Zone?

Yes, and it happens all the time. The obstacle when you rebuild a house in a flood zone is not the water; it is a reclassification. Planning does not treat a demolition and rebuild as a larger extension. It treats…
Posted on 25th August, 2026
by Edward Bouët
A "Sold" board outside a row of period terraced houses, where a conveyancing flood search would flag any flood risk before completion.

What Does Your Conveyancing Solicitor Do About Flood Risk?

Your conveyancing solicitor plays a real but limited part in flood risk. They order the searches that flag it, report the results to you and your lender, and pass on what the seller has disclosed. What they do not do,…
Posted on 24th August, 2026
by Jackie Stone
Muddy first flush run-off draining off a road into a kerbside gully grate during heavy rain.

First flush explained: why the first few millimetres of rain matter most in SuDS

Every storm carries its dirtiest water at the start. In the first minutes of rain, run-off sluices weeks of built-up grime (oil, tyre and brake dust, sediment, metals and nutrients) off roofs, roads and car parks and into the nearest…
Posted on 21st August, 2026
by Ellen Webb
Sedum green roof with a flue and rooflight, a sustainable drainage feature the SuDS strategy template records for a planning application.

The New National SuDS Strategy Templates: What They Are and How to Use Them

In August 2026 the Environment Agency published two national SuDS strategy templates: one for major development and one for non-major development. Each is a free Word form that an applicant fills in and submits with a planning application, so that…
Posted on 20th August, 2026
by Antony Rousou
Aerial view of a caravan and mobile home site beside a large body of silt-laden brown water, illustrating gypsy and traveller site flood risk assessment.

Flood Risk and Drainage for Gypsy and Traveller Sites: The Planning Requirements

A Gypsy and Traveller site flood risk assessment is needed for almost every pitch scheme on land that carries any flood risk, and these applications are judged against a tougher standard than ordinary housing. The reason is the caravan. Under…
Posted on 19th August, 2026
by Jackie Stone
New sewer pipes being laid in a trench, the kind of adoptable network covered by a section 104 agreement.

Section 104 and Section 102 Agreements: A Developer’s Guide to Sewer Adoption

A Section 104 agreement is the contract that gets a development's new sewers taken over and maintained by the water company; a Section 102 agreement does the same job for sewers that are already in the ground. Both sit in…
Posted on 18th August, 2026
by Edward Bouët
Excavator digging a drainage trench by stacked pipes and a survey instrument, the groundworks a Section 106 sewer connection needs.

What is a Section 106 sewer connection? The right to connect, explained

A section 106 sewer connection is the statutory right, under section 106 of the Water Industry Act 1991, for the owner or occupier of a property to connect its drains to the public sewer. It is a right, not a…
Posted on 18th August, 2026
by Edward Bouët
Surface water flooding across flat arable farmland, the kind of surface-water-only site the surface water sequential test exemption applies to.

The Surface Water Sequential Test Exemption: Evidencing It Under Policy F5

The surface water sequential test exemption is the biggest change Policy F5 makes to flood risk decision-making in the August 2026 NPPF. It lets a site at risk of surface water flooding only avoid the sequential test — but only…
Posted on 18th August, 2026
by Edward Bouët
Cover graphic for the NPPF August 2026 over an aerial view of a new-build housing estate, for an article on its flood risk and drainage changes.

NPPF August 2026 Changes: Flood Risk and Drainage Implications for Planning

The NPPF 2026 changes are now live. Government published the new National Planning Policy Framework on 17 August 2026, and it applies to planning decisions in England from the day of publication. For flood risk and drainage this is no…
Posted on 17th August, 2026
by Edward Bouët
Aerial view of a campsite on low-lying farmland beside a watercourse, the setting a campsite flood risk assessment must address.

Campsite and glamping flood risk and drainage: the planning requirements in England

A campsite flood risk assessment is required for any camping, glamping or holiday caravan proposal in Flood Zone 2 or 3, and for sites in Flood Zone 1 that are a hectare or more, sit in a critical drainage area,…
Posted on 17th August, 2026
by Jackie Stone
Oil sheen on wet paving running into a road gully, the run-off an oil separator is fitted to intercept.

Oil Separators and BS EN 858: What the Standard Actually Requires

An oil separator is a below-ground chamber that holds back petrol, diesel and oil from surface water run-off before it leaves a site. The standard behind it is BS EN 858, published in two parts: Part 1 covers how the…
Posted on 14th August, 2026
by Antony Rousou
Historical woodcut of a great flood drowning a village and its church, evoking the back-to-back flooding of Europe's medieval past.

Five floods in two years: what a medieval disaster teaches us about back-to-back flooding

Between the autumn of 1341 and the end of 1343, much of Europe flooded again and again. A study published in Nature in August 2026 counted sixteen major flood events in that short window. Four of them were so large…
Posted on 13th August, 2026
by Edward Bouët
Sun-scorched, drought-baked grassland with dry cracked ground, the parched conditions that trigger burst water mains.

Why do water mains burst in hot weather? The hidden burst season explained

Ask most people when a water main bursts and they picture winter: a hard frost, a deep freeze, the metal splitting as the water inside turns to ice. That is half the story. The other half is playing out right…
Posted on 13th August, 2026
by Freya Pott
Brick house extension in a flood zone under construction, with scaffolding and new timber roof trusses being fitted.

Can I Build a House Extension in a Flood Zone?

Yes, and most of them get built. Wanting a house extension in a flood zone is not the problem; the sticking point is the evidence the council asks for before it will grant permission. Sitting in Flood Zone 2 or…
Posted on 13th August, 2026
by Edward Bouët
Underground drainage pipes and an inspection chamber base of the kind BS EN 752 covers, laid out on site before installation.

BS EN 752 explained: the standard for drains and sewers outside buildings

BS EN 752 is the British and European standard for drain and sewer systems outside buildings. It sets out what those systems have to achieve, and how they should be managed through planning, design, construction, operation and rehabilitation. The objectives…
Posted on 12th August, 2026
by Antony Rousou
Rows of Roman stone arches beside a stone-lined channel, evoking the Roman drainage system and water engineering.

What have the Romans ever done for us? Aside from the drainage, obviously

Ask a Roman what they ever did for us and you would probably get a shrug and a wave at, well, everything. Put the same question to a flood-risk engineer, though, and the answer turns oddly specific: a startling amount…
Posted on 11th August, 2026
by Edward Bouët
Aerial view of Skinningrove village and its beck, the site of the £13m Skinningrove flood alleviation scheme.

Skinningrove Flood Alleviation Scheme: £13m Defences Begin in 2026

Construction has started on the Skinningrove flood alleviation scheme, a £13 million Environment Agency project, delivered with Redcar and Cleveland Borough Council, that will protect more than 100 homes in the coastal village by 2028. At its heart is a…
Posted on 10th August, 2026
by Edward Bouët
Single-storey brick granny annexe attached to the main house, the kind of build a granny annexe flood risk assessment supports.

“Granny Annexe” Flood Risk Assessment: The Planning Rules

A granny annexe is self-contained accommodation built for a relative, usually an elderly parent, either added to a house or converted from a garage, stable or outbuilding. “Granny annexe” is the everyday name; in planning language it is ancillary or…
Posted on 7th August, 2026
by Jackie Stone
Street of large bay-fronted Victorian houses, the kind of property subject to a flood risk assessment for a change of use to HMO.

Do you need a flood risk assessment for a change of use to an HMO?

Usually, yes. A flood risk assessment is required for a change of use to an HMO wherever the site sits in Flood Zone 2 or 3, and in a growing number of Flood Zone 1 cases too. An HMO is…
Posted on 7th August, 2026
by Jackie Stone
Aerial view of a part-built housing development, illustrating flood risk and drainage in the planning process across a large residential site.

Flood risk and drainage in the planning process: where they fit at every stage

If you are applying for planning permission for the first time, the part most likely to catch you out is not the design or the neighbours. It is flood risk and drainage in the planning process. Flooding and surface water…
Posted on 6th August, 2026
by Edward Bouët
Carved stone Town Hall façade, representing the local planning authority that consults a statutory consultee on a planning application.

What is a consultee in a planning application? Statutory consultees explained

A consultee is a body or person the local planning authority asks for a view on your planning application before it makes a decision. Some are named in law and must be consulted on particular kinds of development. These are…
Posted on 5th August, 2026
by Jackie Stone
Blocked road gully holding standing surface water, the kind of drainage failure a flood risk assessment and drainage strategy aim to prevent.

Flood Risk Assessment and Drainage Strategy: Do You Need Both?

Most applications that need one of these documents need the other too. A flood risk assessment and a drainage strategy answer different questions: the first asks whether the site floods and whether your development makes flooding worse somewhere else, the…
Posted on 4th August, 2026
by Antony Rousou
Colourful orange and green office block, the kind of building a flood risk assessment for an office to residential conversion would cover under Class MA.

Do you need a flood risk assessment for an office-to-residential conversion (Class MA)?

Often, yes: a flood risk assessment for an office-to-residential conversion is required whenever the building sits in Flood Zone 2 or 3, because Class MA permitted development still has to clear prior approval, and flooding is one of the matters…
Posted on 3rd August, 2026
by Jackie Stone
Derelict timber-framed and brick barn in an overgrown field, the kind of rural building a flood risk assessment for a barn conversion covers.

Do you need a flood risk assessment for a barn conversion (Class Q)?

Yes — if the barn sits in a flood risk area, a flood risk assessment for a barn conversion is almost always required, even though the work is permitted development. Class Q lets you turn an agricultural building into a…
Posted on 3rd August, 2026
by Jackie Stone
Fire engine and residents clearing mud in Gwaelod-y-Garth, Wales, after the flood behind Unda's quarry flood risk assessment article.

Taff’s Well Quarry Flood: Old Mine Water and the Risk TAN15 Doesn’t Map

On Thursday 30th July 2026, homes in Gwaelod-y-Garth, on the north-western edge of Cardiff, flooded minutes after a planned blast at Taff's Well Quarry on the Lesser Garth, the limestone ridge above the village. The Health and Safety Executive (HSE)…
Posted on 31st July, 2026
by Edward Bouët
Rainwater beading on an EV charge point connector, the exposed kit a flood risk assessment for EV charging must account for.

Flood Risk and Drainage for EV Charging Infrastructure: What Developers Need to Know

There were 119,080 public chargers on the UK network on 1 April 2026, and 27,372 of them were rated 50kW or above. Almost all of it went in on land nobody picked for its flood characteristics: retail car parks, filling-station…
Posted on 30th July, 2026
by Jackie Stone
Flooded garden and part-submerged shed, showing existing flooding a betterment planning condition cannot require a developer to fix.

Can a Planning Condition Make You Fix a Flood Problem You Didn’t Cause?

Almost every developer who has taken a drainage condition through to discharge has met some version of this. The site floods. The gardens next door flood. The culvert downstream has been surcharging since long before anyone applied for anything. And…
Posted on 29th July, 2026
by Edward Bouët
An ageing timber and iron sea defence on a tidal shoreline, the kind of structure a shoreline management plan decides whether to maintain.

Shoreline Management Plans Explained: Hold the Line, Managed Realignment and No Active Intervention

England's coast runs to roughly 6,000km, and nearly all of it is covered by a shoreline management plan: the document that decides whether a stretch of shoreline gets defended, left alone, or allowed to move. A shoreline management plan (SMP)…
Posted on 27th July, 2026
by Edward Bouët
Colourful seafront houses above an eroded cliff edge, the sharp end of the coastal erosion compensation UK debate.

Erosion of trust: the government’s own words versus its coastal erosion grant

There is no coastal erosion compensation in the UK. If the sea takes your home, there is no insurance payout and no statutory compensation for the land or the building. Until 15 July 2026 there was a demolition grant that…
Posted on 24th July, 2026
by Edward Bouët
Large period building in open grounds, the kind of property a flood risk assessment for a care home usually covers.

Flood Risk Assessment for a Care Home, Children’s Home or Supported Living

A flood risk assessment for a care home, children's home or supported living scheme is needed wherever the site sits in Flood Zone 2 or 3, and increasingly in Flood Zone 1 as well. The classification these uses take is…
Posted on 23rd July, 2026
by Jackie Stone
Collapsed clifftop road ending at an eroding coastline, the kind of loss that sea level rise planning must anticipate beyond 2100.

Sea Level Rise and Planning: Why 2100 Is No Longer the End of the Story

For most of UK practice, sea level rise and planning meet at a single tidy horizon: the end of this century. Flood risk assessments run their allowances out to the 2120s, defence schemes are appraised on similar timescales, and almost…
Posted on 22nd July, 2026
by Edward Bouët
Andy Burnham at a press microphone as the Burnham government planning agenda takes shape.

What Will the Burnham Government Mean for Planning, Housing and Flood Risk?

Andy Burnham became Prime Minister on 20 July 2026, and the Burnham government's planning agenda is already taking shape. The cabinet is appointed, the first speech has been given, and the big in-flight reforms (the new NPPF, the national scheme…
Posted on 21st July, 2026
by Edward Bouët
Rotary drilling rig mast caked in slurry on a housing development, of the kind used for deeper ground investigation boring.

Ground Investigation for Drainage and Flood Risk: What a Planning Application Needs

A ground investigation establishes what lies beneath a site: the soils, the rock under them, the depth of any made ground, and where the water sits. Drainage, foundations and earthworks can then be designed against measured conditions instead of assumed…
Posted on 20th July, 2026
by Ellen Webb
Surrey County Council's County Hall sign, one of the county councils being replaced under local government reorganisation.

Local government reorganisation 2026: what England’s council shake-up means for flood risk and planning

England is part-way through the biggest reshaping of its councils in fifty years. Local government reorganisation replaces the two-tier system of county and district councils with single unitary authorities, and on 16 July 2026 the government confirmed the shift for…
Posted on 17th July, 2026
by Edward Bouët
British Geological Survey logo and wordmark set over a photograph of exposed soil, stones and layered ground.

The British Geological Survey explained: what BGS data tells you about a site

The British Geological Survey is the UK's national geological survey and the public custodian of its geoscience records: a research centre of the Natural Environment Research Council, founded in 1835, holding the national geological map and more than a million…
Posted on 16th July, 2026
by Emma Jeffery
Open foul drainage inspection chamber with weathered pipework, the kind of accessible access point Building Regulations Part H foul water rules require.

Building Regulations Part H: Foul Water Explained

Building Regulations Part H is the part of the building rules that governs foul water drainage: how the used water from a building's toilets, sinks, baths and appliances is carried away safely. If you are building, extending or converting anything…
Posted on 15th July, 2026
by Antony Rousou
Contractor cutting drainage pipework on a construction site, work that can only begin after discharge of planning conditions.

Discharge of Planning Conditions: Process, Timescales and Costs (2026)

Discharge of planning conditions is the formal step of asking your local planning authority to confirm, in writing, that a condition attached to your planning permission has been satisfied. In planning terms it is an “application for approval of details…
Posted on 14th July, 2026
by Antony Rousou
Traffic cones in floodwater behind sandbags, illustrating a CON29DW report guide to drainage and water searches.

What Is a CON29DW Report? The Drainage and Water Search Explained

A CON29DW report is the official drainage and water search a conveyancer orders during a property purchase. Compiled from the water company's own records, it answers 26 standardised enquiries about how a property connects to the public water and sewer…
Posted on 10th July, 2026
by Antony Rousou
Vegetated SuDS swale beside a new-build residential street, an above-ground infiltration feature used within the SuDS hierarchy.

The SuDS Hierarchy Explained

The SuDS hierarchy is the order in which a development has to try to get rid of its surface water: reuse it first, then let it soak into the ground, then send it to a watercourse, then a surface water…
Posted on 9th July, 2026
by Edward Bouët
Tennis ball splashing on a rain-soaked court, illustrating why grass court drainage decides when play can continue.

Why Does Rain Stop Play at Wimbledon? The Science of Grass Court Drainage

Every Wimbledon has the same ritual. A few spots of rain, the umpire calls a halt, and within seconds the ground staff are sprinting the covers across the grass. It looks like an overreaction on a warm July afternoon. It…
Posted on 8th July, 2026
by Edward Bouët
Boot striking a mud-flecked ball on a floodlit stadium pitch, the wet playing surface that football pitch drainage keeps firm.

How Football Pitch Drainage Works: Lessons from the 2026 World Cup

Watch a World Cup match in a downpour and the ball still runs true. There are no puddles on the halfway line, no spray kicking up at every pass. That is not luck. Football pitch drainage is a piece of…
Posted on 7th July, 2026
by Edward Bouët
A weir and riverside building on a chalk stream, the kind of watercourse managed under the Romsey flood alleviation scheme.

Romsey Flood Alleviation Scheme: How New Defences Are Reducing Flood Risk in 2026

The Romsey flood alleviation scheme has just been strengthened again. In May 2026 the Environment Agency finished raising Stockbridge Road near Timsbury by around 40 centimetres and rebuilt the flood defence at a nearby weed-recovery compound: the latest step in…
Posted on 6th July, 2026
by Edward Bouët
Two construction professionals disagreeing over site plans, showing the gap between building control and planning.

Do building control and planning talk to each other? Drainage, SuDS and the gap between them

A building control officer tells you the simplest thing to do is run the surface water into the sewer. Your planning condition says infiltration first, greenfield runoff rates, attenuation for a one-in-100-year storm. Both cannot be right, and only one…
Posted on 3rd July, 2026
by Edward Bouët
Illustrative flood performance certificate beside a storm wave breaking over a harbour wall, with papercraft homes and hills.

Flood Performance Certificates: What They Are and When They Start

A flood performance certificate (FPC) is a planned rating of how well a home keeps floodwater out and how quickly it recovers when water gets in, in the way an Energy Performance Certificate rates energy use. Flood Re confirmed on…
Posted on 3rd July, 2026
by Jackie Stone
Part-built house clad in scaffolding behind a new timber fence, illustrating a retrospective planning application.

Retrospective Planning Permission: The 2026 Guide

Retrospective planning permission is planning permission applied for after building work has already started or finished. It is made under Section 73A of the Town and Country Planning Act 1990. It is then judged in exactly the same way as…
Posted on 2nd July, 2026
by Edward Bouët
Aerial view of algae-covered wastewater treatment tanks, the kind of nutrient pollution behind nutrient neutrality rules in planning.

Nutrient Neutrality in Planning: Catchments, Budgets and Credits

Nutrient neutrality is a legal test that prevents a local planning authority granting permission unless the extra nitrogen or phosphorus a development would send to a protected river, estuary or wetland is cancelled out. It is not a policy consideration…
Posted on 30th June, 2026
by Jackie Stone
Surface water drainage chamber and pipe under construction on a commercial development, the kind of works a SuDS proforma summarises.

What Is a SuDS Proforma and When Is It Required?

A SuDS proforma — also called a drainage proforma or sustainable drainage proforma — is a standardised summary form that goes in with a sustainable drainage strategy on a planning application. It sets out the key drainage information in a…
Posted on 26th June, 2026
by Antony Rousou
Tractor working through vine rows in a water-stressed South East vineyard, a backdrop to water neutrality in planning.

What is Water Neutrality? The 2026 Position for Planning

Water neutrality is a planning requirement that a development must not increase the total amount of water taken from the environment for public supply across a defined area. The extra demand created by new homes or buildings has to be…
Posted on 24th June, 2026
by Jackie Stone
Policy and checklist graphics over a laptop, representing a planning application invalidated for missing flood risk and drainage documents.

Planning Application Invalidated? The Flood Risk and Drainage Documents You’re Missing

A planning application invalidated for flood risk or drainage almost always comes down to one thing: a document the local planning authority treats as mandatory is missing from the submission. Most often that is a flood risk assessment (FRA), a…
Posted on 22nd June, 2026
by Antony Rousou
Heavy rain falling from storm clouds over a rough UK coast, illustrating the climate whiplash between flood and drought.

Climate Whiplash: What New UK River Research Means for Flood and Drought Risk

Climate whiplash, the abrupt swing between flood and drought as the climate warms, is set to become more common across the UK, according to major new research led by the University of East Anglia's Tyndall Centre. The study modelled almost…
Posted on 19th June, 2026
by Jackie Stone
The Royal Courts of Justice in London, where High Court rulings on the exception test and the planning balance are handed down.

Sequential test, exception test and the planning balance: lessons from the Yatton judgment

When a flood risk scheme fails the sequential test, does the decision end there? The High Court has now answered plainly. In *North Somerset District Council v Secretary of State for Housing, Communities and Local Government* [2026] EWHC 1430 (Admin),…
Posted on 18th June, 2026
by Edward Bouët
Aerial view of Somerset Levels flooding, with brown floodwater across farmland either side of a raised road.

Why the Somerset Levels flood — and what £50m will (and won’t) fix

The Somerset Levels flood because they are a low-lying former wetland, much of which sits at or below the level of the rivers and tides meant to drain it. In a wet winter, water arrives faster than the catchment can…
Posted on 17th June, 2026
by Edward Bouët
Undulating green roof beside a lake at sunset, illustrating the four pillars of SuDS in modern green infrastructure.

The Four Pillars of SuDS Explained: Quantity, Quality, Amenity & Biodiversity

The four pillars of SuDS are water quantity, water quality, amenity and biodiversity — the four objectives a well-designed sustainable drainage system is meant to deliver at the same time. They come from the CIRIA SuDS Manual (C753) and now…
Posted on 16th June, 2026
by Antony Rousou
Close-up of permeable block paving on an access road, the kind of surface used as permeable paving for planning applications.

Permeable Paving for Planning Applications: When It Works and When It Doesn’t

Permeable paving is one of the most common SuDS features used in drainage strategies for planning applications, and on the right site it is one of the most useful. It lets rainfall pass through the surface into a stone sub-base…
Posted on 15th June, 2026
by Antony Rousou
Leaky dams built from logs spanning a grassy upland channel to slow the flow and hold water back.

Leaky Dams and Flood Risk: What They Do, Where They Work, and What They Can’t Fix

Anyone who has watched the latest series of Clarkson's Farm will have seen Jeremy Clarkson wading into a stream at Diddly Squat to build what he gleefully describes, after a bit of reading on the government's website, as "large, leaky,…
Posted on 13th June, 2026
by Charlotte Stone
urface water flooding across an urban London street, the kind of local flooding a critical drainage area is mapped to manage.

What Is a Critical Drainage Area? Planning and FRA Rules for 2026

A critical drainage area is land where surface water runoff, drainage capacity or overland flow routes are sensitive enough that the planning authority wants flood risk settled before permission is granted, not after. If your site sits inside one, it…
Posted on 12th June, 2026
by Antony Rousou
xcavated soakaway trial pit illustrating the question 'do you need infiltration testing' for a planning drainage strategy.

When Is Infiltration Testing Required for Planning?

Infiltration testing is required when your drainage design relies on getting surface water into the ground and the planning authority wants evidence the ground will take it. In practice that means soakaways, infiltration trenches or permeable paving over an infiltrating…
Posted on 11th June, 2026
by Antony Rousou
Sea level rise flood risk sign on Eastbourne beach showing predicted coastal sea level rise by decade to the 2120s.

Sea level rise in the UK: how much, how fast, and what it means for coastal flood risk

Sea level rise around the UK has stopped being a projection to argue over. It is a measured record. Mean sea level around these islands has risen by about 20.1 cm since 1901, and roughly two-thirds of that rise has…
Posted on 10th June, 2026
by Edward Bouët
Aerial view of a masonry reservoir dam, a flood defence whose design standard still leaves residual flood risk downstream.

Residual Flood Risk Explained: How It’s Assessed and Managed

Residual flood risk is the risk left over after defences, drainage and mitigation have done what they can. No scheme removes risk entirely. A defended site still floods if a barrier is overtopped, if a defence breaches, or if a…
Posted on 9th June, 2026
by Edward Bouët
City of London insurance district, home to the market behind the insurers NPPF flood risk warning over new homes.

Why the Insurance Industry Is Warning Against the NPPF Flood Risk Changes

In early March 2026, as the government's consultation on its revised National Planning Policy Framework drew to a close, seventeen of the most significant names in UK flood risk signed a single joint letter to ministers. Insurers, mortgage lenders, brokers…
Posted on 8th June, 2026
by Jackie Stone
Sandbags stacked against a front door in floodwater, the residual risk a long term flood risk map describes.

Long Term Flood Risk Map: What It Shows and How to Read It

The long term flood risk map is the Environment Agency's public service for England. It shows the chance of flooding at a location from rivers and the sea, surface water, reservoirs and, where the data exists, groundwater, reported in four…
Posted on 5th June, 2026
by Jackie Stone
Completed house with floodable void openings in the brick undercroft, raising the finished floor above flood level.

Can You Build a House on Stilts in a Flood Zone? Floodable Voids Explained

Yes, you can build a house on stilts in a flood zone in England, and a floodable void is the engineering that lets you do it. A floodable void is an open space beneath a building that floodwater flows into,…
Posted on 4th June, 2026
by Jesy Ferry
Groundwater flood risk map UK showing groundwater flood warnings (triangles) and alerts (dots) on the Chalk aquifer in Wessex, February 2020.

Water Table and Groundwater Flood Maps in the UK: How to Check a Site

There is no single official water table map for the UK, and no national groundwater flood map either. Rivers and the sea have both. Groundwater has neither. What exists instead is a scatter of separate datasets, each built for a…
Posted on 2nd June, 2026
by Jackie Stone
Waterlogged farmland with rainwater pooling in the furrows, showing surface water flooding as a planning constraint.

Surface Water Flooding and Planning: A Complete Guide for Developers

Surface water is the most widespread source of flood risk in England, and the August 2026 National Planning Policy Framework has made how you handle it decisive at the planning stage. Getting surface water flooding and planning right now turns…
Posted on 1st June, 2026
by Edward Bouët
Surface water pooled on a cobbled urban street, reflecting nearby buildings after rainfall.

EA Flood Map for Planning: May 2026 Update — Surface Water Climate Change Data

On 28th May 2026 the Environment Agency added surface water climate change extents and banded depth layers to the Flood Map for Planning. The Check Your Long Term Flood Risk (CYLTFR) surface water data should no longer be used for…
Posted on 28th May, 2026
by Edward Bouët
Wildflower-fringed wet pond with reeds and willows, a vegetated SuDS feature that shows how SuDS and biodiversity net gain overlap.

Do SuDS count towards biodiversity net gain? What actually scores

Yes, sustainable drainage systems can count towards biodiversity net gain, but only the parts of a SuDS scheme that create real, lasting habitat, and only for what that habitat is genuinely worth. A planted basin, a wet pond or a…
Posted on 27th May, 2026
by Jackie Stone
Residential development under construction in scaffolding, the kind of new-build scheme a BREEAM flood risk assessment supports.

BREEAM Flood Risk Assessments Explained

BREEAM is the leading sustainability standard for UK buildings, and how a scheme handles flood risk is one of the things it scores. A BREEAM flood risk assessment is a site-specific study of a development's flood risk, written so the…
Posted on 25th May, 2026
by Emma Jeffery
Standing floodwater across a rural lane between hedgerows, showing the prolonged flooding that saturated ground can cause, demonstrating the need for a groundwater flood risk assessment.

Groundwater Flood Risk and Planning Applications: What Developers Need to Submit

Key takeaways If your site needs a Flood Risk Assessment, that FRA must assess groundwater — it is not optional under the NPPF and Planning Practice Guidance. The national flood maps do not show groundwater. Screen with the BGS Susceptibility…
Posted on 22nd May, 2026
by Edward Bouët
AI chatbot apps including ChatGPT, Claude and Gemini on a smartphone, raising the question can AI write a flood risk assessment.

Can AI Write a Flood Risk Assessment?

Ask any chatbot to write a flood risk assessment and it will hand you a confident, well-formatted document in seconds. That is the easy part. It is also the misleading part, because a flood risk assessment is not really a…
Posted on 20th May, 2026
by Edward Bouët
Water butts collecting greenhouse roof runoff, a small-scale SuDS feature of the kind the Surface Water Investment Model appraises.

EA SWIM Explained: Building a Business Case for Small-Scale SuDS Investment

The Surface Water Investment Model (SWIM) is an Environment Agency approach, published on 18 May 2026, for building a business case to invest in many small sustainable drainage features across a wide area, rather than one large scheme, so their…
Posted on 19th May, 2026
by Antony Rousou
Sandbags lined along a commercial roller-shutter door and fire exit to hold back floodwater, a temporary flood-resistance measure.

Property Flood Resilience and Planning: The 2025 FloodReady Action Plan, the CIRIA Code and Build Back Better

Property flood resilience (PFR) has moved from the margins of flood policy towards the centre of it. The 2025 FloodReady action plan, the maturing CIRIA Code of Practice, and insurance-side schemes like Build Back Better have made the idea of…
Posted on 14th May, 2026
by Jackie Stone
Floodlit outdoor padel courts beside open grass, the uncovered layout that keeps padel court drainage straightforward.

Padel Court Drainage and Flood Risk: What the Planning System Actually Asks For

Padel court drainage is the part of a padel planning application that almost nobody scopes, because the court is built to drain and everyone assumes that settles the question. It does not. The LTA's own construction guidance specifies a porous…
Posted on 12th May, 2026
by Freya Pott
Flooded low-lying UK farmland at sunset, with standing water reflecting trees and sky across a fenced field boundary.

The Flood Knowledge Gap Between Communities and Institutions

In 1724, a local historian described one Berkshire village as "a low and watery place" where "water is a dominant theme … with disastrous floods, both within and beyond living memory." More than two centuries later, that village still requires…
Posted on 11th May, 2026
by Edward Bouët
LiDAR elevation model of a river and floodplain, the kind of terrain data behind hydraulic models built to the EA river modelling technical standards.

EA River Modelling Technical Standards (2026): What Flood Risk Assessments Must Demonstrate

Hydraulic modelling sits behind almost every detailed flood risk assessment, and the Environment Agency sets the standard for how those models are built and reviewed. The EA river modelling technical standards define what a credible model looks like and what…
Posted on 8th May, 2026
by Emma Jeffery
Victorian townhouses on a London street, the typical subject of flood risk assessment converting house to flats.

Do you need a flood risk assessment to convert a house into flats?

Usually, yes. A flood risk assessment when converting a house into flats is required wherever the site sits in Flood Zone 2 or 3, and in a growing number of Flood Zone 1 cases too. Flats are still homes, so…
Posted on 7th May, 2026
by Jackie Stone
Flooded field and wetland landscape showing natural water storage in a catchment-scale flood resilience context.

Nature-Based Solutions and Flood Risk: What the 2026 NPPF Now Requires

Nature-based solutions have moved from advocacy into planning policy. The National Planning Policy Framework published on 17 August 2026 defines them, asks development plans to make as much use of natural flood management as possible, and asks development proposals themselves…
Posted on 5th May, 2026
by Charlotte Stone
Surface water flooding in a London street with vehicles driving through standing water after heavy rainfall

Surface Water Flood Risk in England’s Towns and Cities: What the Data Now Shows

Surface water flood risk has become the defining flood problem in England's towns and cities. New national data shows that most homes now judged to be at high flood risk are urban, and the cause is rarely a river bursting…
Posted on 29th April, 2026
by Edward Bouët
ow lying wetland landscape in the Fens with open water, reeds and storm clouds showing flood prone terrain

Fens 2100+ explained: what the Environment Agency’s evidence actually says

Fens 2100+ is the Environment Agency's long-term flood risk and water management programme for the Lincolnshire and Cambridgeshire Fens, run in partnership with Internal Drainage Boards, local authorities and water companies. In April 2026 it published a summary baseline report,…
Posted on 28th April, 2026
by Emma Jeffery
Sunlight through a silver birch woodland with ferns and grasses — the kind of vegetation that helps soils absorb rainfall.

Sponge cities in the UK: what the idea now means for planning and drainage

Sponge cities are urban areas built to absorb, store and slowly release rainfall instead of piping it away as fast as possible. The phrase came out of China a decade ago. In Britain it has mostly been discussed as something…
Posted on 24th April, 2026
by Charlotte Stone
Heavy rain on an urban street, illustrating surface water flooding pressures relevant to forecasting and planning.

From 6-Hour Warning to Spade in Ground: What SWFFIP Means for Planning

On 16th April the Flood Forecasting Centre published the results of SWFFIP, the Surface Water Flood Forecasting Improvement Project. The programme brings two models into fuller operational use: the Surface Water Flooding Hazard Impact Model (SWFHIM), which has been running…
Posted on 21st April, 2026
by Jackie Stone
Flooded rural road behind a red Flood warning sign, the kind of event behind the question "are flood maps accurate" at the property scale.

Are Flood Maps Accurate? Why a Property Can Flood When the Map Says Low Risk (and Vice Versa)

Are flood maps accurate? At the scale they are built for, meaning a region, a catchment or a whole postcode, broadly yes. At the scale that matters when you are buying a house or designing a single building, often not.…
Posted on 17th April, 2026
by Jackie Stone
Diagram of people drilling a groundwater monitoring borehole, required as part of groundwater monitoring for planning.

Groundwater Monitoring for Planning: Requirements, Timing and Delays

Groundwater monitoring for planning is the process of measuring how the water table beneath a site rises and falls over the seasons, usually to prove that an infiltration-based drainage scheme will actually work. It is most often needed where Sustainable…
Posted on 14th April, 2026
by Ellen Webb
Flooded tree-lined avenue in the Netherlands behind a Dutch high-water sign, showing why source control matters in UK drainage.

Source Control in UK Drainage: SuDS at Plot Level

Source control means managing rainfall as close as possible to where it lands, before it has a chance to run off into the wider drainage network. It sits at the very top of the SuDS hierarchy, and in principle it…
Posted on 9th April, 2026
by Edward Bouët
Aerial view of floodwater around a rural house and outbuildings, the kind of event a section 19 flood investigation records.

Why Some Floods Get Investigated and Others Don’t: Section 19 Reports Explained

A Section 19 flood investigation is the report a lead local flood authority publishes after a flood it has decided is serious enough to look into. It records what flooded, why it flooded, which authorities held responsibilities, and what each…
Posted on 7th April, 2026
by Edward Bouët
Colourful seafront houses behind a wide shingle beach, the kind of coastal setting a holiday let flood risk assessment must address.

The barn or the field? Flood risk for holiday lets, cabins and farm diversification

A holiday let flood risk assessment is required for any permanent holiday unit in Flood Zone 2 or 3, and for units in Flood Zone 1 on a site of a hectare or more, in a critical drainage area, or…
Posted on 6th April, 2026
by Edward Bouët
Measured site survey plan showing plot boundaries, dwellings and existing features, the base information used to develop drainage for planning permission.

What Drainage Information Is Needed for Planning Permission?

For years it was standard practice to secure surface water drainage by planning condition and work up the detailed design after permission was granted. That route still exists. What has changed is how much a planning application has to demonstrate…
Posted on 2nd April, 2026
by Edward Bouët
Planning Appeals 2026 Flood Risk & Drainage Changes

Planning Appeals 2026: Why Flood Risk and Drainage Must Be Right First Time

A planning appeal on flood risk grounds is now, in most cases, decided on the evidence that was already sitting in the application file. Since 1 April 2026 most appeals in England run through a streamlined written representations procedure, and…
Posted on 27th March, 2026
by Emma Jeffery
Groundwater Flooding, Listed Building, and Planning Lessons from Key Case

How flood defence works can raise groundwater, and who pays for the damage

Flood defences are built to keep water out. Sometimes they change where the water goes instead. The relationship between flood defence works and groundwater has now been tested twice in the Upper Tribunal, and both decisions went against the Environment…
Posted on 26th March, 2026
by Edward Bouët
Drainage outfall pipes discharging to a watercourse beside a hand marking a site plan, illustrating an LLFA objection.

LLFA Objection to a Planning Application: Why Drainage Strategies Are Rejected and How to Resolve It

An LLFA objection to a planning application is one of the most common hurdles a development can hit, and one of the most resolvable. It rarely means the scheme is unacceptable in principle. It means the Lead Local Flood Authority,…
Posted on 23rd March, 2026
by Edward Bouët
Environment Agency Objection to Planning Application (Flood Risk)

Environment Agency Objection to Your Planning Application (Flood Risk): How to Resolve It

An Environment Agency objection to a planning application on flood risk grounds is unsettling, but it is rarely the end of a scheme. In most cases it means the flood risk evidence in front of the local planning authority is…
Posted on 23rd March, 2026
by Edward Bouët
Aerial view of flooded farmland across a wide river floodplain, illustrating flood risk in England's Land Use Framework.

The Land Use Framework and flood risk: what it actually changes

The Land Use Framework is the government's first national statement of how England's land should be shared between housing, farming, energy and nature. Defra published it on 18 March 2026, and it is built on flood figures that ought to…
Posted on 20th March, 2026
by Charlotte Stone
What Is Environment Agency Flood Data

Environment Agency Product 4 Flood Data: How to Request It

Environment Agency Product 4 flood data is the detailed dataset most Flood Risk Assessments in England are built on, and it is requested free through the Flood Map for Planning service with a statutory 20-working-day deadline attached. This guide covers…
Posted on 20th March, 2026
by Edward Bouët
£1.4bn Flood Defence Funding 202627 Explained

£1.4bn Flood Defence Funding 2026/27 Explained

The UK government has announced £1.4 billion of flood defence funding for 2026 / 27, supporting more than 600 schemes across England, as set out in the official £1.4bn flood investment announcement. The funding is intended to reduce flood risk…
Posted on 18th March, 2026
by Edward Bouët
Consultant making notes beside a laptop while working through how to do a flood risk assessment for planning.

How to Do a Flood Risk Assessment for Planning

A flood risk assessment (FRA) is a technical report that identifies how a site could flood, now and over the lifetime of a development, and shows a planning authority that the proposal will be safe and will not make flooding…
Posted on 17th March, 2026
by Edward Bouët
Calculator, pen and sterling banknotes, illustrating how much a flood risk assessment costs.

Flood Risk Assessment Cost: What Drives the Price and Why Bespoke Beats Fixed

Ask ten flood risk consultants what a flood risk assessment costs and the honest ones all say the same thing: it depends on the site. Anyone who quotes a firm figure before they have seen yours is guessing. The cost…
Posted on 16th March, 2026
by Edward Bouët
Carved stone flood marker recording the height reached by the 1947 floods on 14 March, above an earlier August 1879 flood mark.

The great floods of 1947: 690,000 acres under water, and what the record still doesn’t show

In March 1947, rapid snowmelt onto ground that had been frozen for six weeks produced the largest river flood England has seen in the last hundred years. At the peak, the Minister of Agriculture told the Commons, 690,000 acres were…
Posted on 13th March, 2026
by Edward Bouët
Hands holding a piggy bank and a clock, the cost-and-time trade-off behind the question can I do my own flood risk assessment.

Why an Expert Should Write Your Flood Risk Assessment

A flood risk assessment looks like a document. What you are buying is the judgement behind it. Which source of flooding actually governs the site, whether the published mapping can be trusted at this scale, what the reviewing authority will…
Posted on 11th March, 2026
by Edward Bouët
Warning sign on a newspaper headline about major floods, illustrating why a conveyancing flood report is not enough for planning.

Why a Conveyancing Flood Report Won’t Pass Planning (And What Will)

A conveyancing flood report will not pass planning, because it answers a different question from the one a planning authority is asking. A conveyancing flood report screens an existing property for a buyer or a lender. A planning flood risk…
Posted on 10th March, 2026
by Edward Bouët
New CIRIA guidance encourages communities to help maintain local flood defences

CIRIA C821 Explained: Community Maintenance of Flood Risk Assets

CIRIA C821 is a free three-part guidance suite, published in 2025, on how community groups can help maintain local flood risk assets and how the authorities responsible for those assets should work with them. Its value is the line it…
Posted on 6th March, 2026
by Jackie Stone
Unda at the Manor Royal Jobs Fair Crawley Town Hall

Unda at the Manor Royal Jobs Fair – Crawley Town Hall

Today, members of the Unda team are at Crawley Town Hall taking part in the Manor Royal BID Jobs Fair, meeting local jobseekers and showcasing career opportunities within the business. Representing Unda at the event are Jackie and Antony, who…
Posted on 6th March, 2026
by Jackie Stone
River weir and footbridge at dusk with an electricity pylon behind, illustrating flood funding reform and FCERM guidance.

Flood Funding Reform 2026: The New FCERM Guidance Explained

Defra has published new guidance governing how flood and coastal erosion schemes in England will be funded and prioritised from 2026 onwards. This is not a minor procedural update. It reshapes how projects are classified, how funding levels are calculated,…
Posted on 3rd March, 2026
by Jackie Stone
Flooded high street with stone-built shops and floodwater reflecting the buildings, illustrating flood vulnerability.

Flood Risk Vulnerability Classification: The 2026 NPPF Guide (Annex F, Table 2)

Flood risk vulnerability classification is the system in the National Planning Policy Framework (NPPF) that sorts every type of development by how badly flooding would affect it: by consequence, not probability. It places each use in one of five categories,…
Posted on 2nd March, 2026
by Edward Bouët
Wales’ £85m Flood Investment Explained

Wales’ £85m Flood Investment Explained

The Welsh Government has announced £85 million of funding for flood and coastal erosion risk management in Wales for 2026 – 27, describing it as the highest annual allocation ever delivered. The headline figure is significant. It builds on more…
Posted on 27th February, 2026
by Edward Bouët
Dirty Business and the Politics of Britain’s Water Infrastructure.

Sewage Capacity and Planning: Why Water Infrastructure Now Decides What Gets Built

Channel 4's Dirty Business was reviewed as a "blast of controlled fury" aimed at Britain's water industry. The drama was about sewage. The consequence for anyone trying to build is narrower and far more practical: in parts of England, sewage…
Posted on 25th February, 2026
by Jackie Stone
Living with Water What the UK Can Learn from Venice’s Everyday Flooding

Acqua alta: how Venice lives with flooding, and what the UK takes from it

Acqua alta is the tidal flooding that covers parts of Venice several dozen times a year, and the city stays open through almost all of it. The reason is not the barrier at the lagoon mouth. It is that the…
Posted on 23rd February, 2026
by Edward Bouët
One in Nine New Homes in Flood Risk Areas

New Homes in Flood Risk Areas: Is 11% Really Evidence of Planning Failure?

On its own, the one-in-nine figure does not prove that planning has failed. When Aviva reported that 11% of new homes in flood risk areas were built where flooding is a medium or high risk, the headline landed as a…
Posted on 23rd February, 2026
by Jackie Stone
Red and white Flood warning sign in front of a country lane under water, illustrating the types of flooding.

Types of Flooding Explained: Sources of Flood Risk

Flooding can arise from several different sources, and understanding the types of flooding that may affect a site is an essential part of assessing flood risk for property, land and development proposals. While many people associate flooding primarily with rivers…
Posted on 19th February, 2026
by Edward Bouët
What Is Infrastructure Flooding Causes, Risks and Planning Implications

What Is Infrastructure Flooding? Causes, Risks and Planning Implications

Flooding can also occur when water escapes from man-made infrastructure such as canals, water mains, culverts or other engineered systems. This type of flooding is often referred to as infrastructure flooding or artificial source flooding. Infrastructure flooding occurs when water…
Posted on 18th February, 2026
by Edward Bouët
What Is Reservoir Flooding Causes, Risks and Planning Implications

What Is Reservoir Flooding? Causes, Risks and Planning Implications

Flooding can occur from the failure or overtopping of large raised water bodies such as reservoirs. This type of flooding is known as reservoir flooding. Reservoir flooding occurs when water stored behind a reservoir dam or embankment is suddenly released…
Posted on 18th February, 2026
by Edward Bouët
What Is Sewer Flooding Causes, Risks and Planning Implications

Sewer Flooding: Causes, Responsibility and What Buyers Can Check

Sewer flooding happens when wastewater escapes from a drain or sewer: into a building, out across gardens and land, or back up through toilets and sinks that can no longer empty. Heavy rain overloading the network is the usual trigger,…
Posted on 18th February, 2026
by Edward Bouët
Waterlogged meadow with standing surface water reflecting trees, illustrating groundwater flooding rising to ground level.

What Is Groundwater Flooding? Causes, Risks and Planning Implications

Groundwater flooding happens when water rises up from beneath the ground rather than spilling in from a river or running across the surface. After long, wet periods the water table — the level below which the ground is saturated —…
Posted on 18th February, 2026
by Edward Bouët
What Is Tidal Sea Flooding Causes, Risks and Planning Implications

What Is Tidal (Sea) Flooding? Causes, Risks and Planning Implications

Flooding in coastal areas is often caused by the sea rather than rivers or rainfall. This type of flooding is known as tidal flooding, sometimes referred to as coastal flooding or sea flooding. Tidal flooding occurs when sea water moves…
Posted on 18th February, 2026
by Edward Bouët
What Is Fluvial River Flooding Causes, Risks and Planning Implications

What Is Fluvial (River) Flooding? Causes, Risks and Planning Implications

Flooding is often associated with rivers overflowing their banks, and this is known as fluvial flooding, sometimes referred to as river flooding. Fluvial flooding occurs when the volume of water flowing through a river channel exceeds its capacity. When this…
Posted on 18th February, 2026
by Edward Bouët
What Is Pluvial Surface Water Flooding Causes, Risks and Planning Implication

What Is Pluvial (Surface Water) Flooding? Causes, Risks and Planning Implications

Surface water flooding, also called pluvial flooding, happens when rainfall lands faster than the ground can absorb it and faster than drains and watercourses can carry it away, so water runs across the surface and collects in low points. That…
Posted on 18th February, 2026
by Edward Bouët
Temporary flood defences holding back the River Severn from riverside properties in the flood zone at Bewdley.

Still in a Flood Zone After New Flood Defences? What Actually Changes

A new flood wall goes up, an embankment is raised, a storage basin is finished after years of consultation. Then you open the map and nothing has moved. If you are still in a flood zone after flood defences have…
Posted on 16th February, 2026
by Edward Bouët
Why Is My House in a Flood Zone if It Has Never Flooded?

Why Is My House in a Flood Zone if It Has Never Flooded?

"Why is my house in a flood zone? We have lived here for years and it has never flooded." Being never flooded but in a flood zone is not a contradiction, and it is not a mistake on the map.…
Posted on 16th February, 2026
by Edward Bouët
Aerial view of a new housing estate under construction, illustrating a development approved despite flood risk fears.

Approved Despite Flood Risk? What the 2026 NPPF Actually Requires

“Approved despite flood risk fears” is a stock headline in England’s local press, and it usually means the same thing: residents describe flooded roads or overwhelmed drains, councillors record their worry, and permission is granted anyway. The reading most people…
Posted on 16th February, 2026
by Edward Bouët
River Thames in flood at a riverside town with a swan and a bridge, illustrating downstream flood risk from the Jubilee River.

Jubilee River Flood Relief Channel: Route, Operation and Downstream Risk

The Jubilee River is an 11.6 km flood relief channel that takes water out of the River Thames at Taplow, carries it around Maidenhead, Windsor and Eton, and hands it back to the Thames between Eton and Datchet. It opened…
Posted on 12th February, 2026
by Edward Bouët
Aerial view of the River Thames in flood around a marina and homes, illustrating River Thames Scheme delays.

What is the River Thames Scheme, and why is it delayed?

The River Thames Scheme is a planned flood relief project on the lower Thames between Egham and Teddington, led by the Environment Agency and Surrey County Council. It would cut two new flood channels through Runnymede and Spelthorne and upgrade…
Posted on 9th February, 2026
by Edward Bouët
Aerial view of a large building being refurbished in Stoke-on-Trent, illustrating flood risk investment and regeneration.

Fowlea Brook flood scheme: what £12.6m has changed in Stoke-on-Trent

The Fowlea Brook flood scheme is a £12.6 million Environment Agency project, completed in February 2026, that has rebuilt the defences along a constrained urban watercourse running through the centre of Stoke-on-Trent. It reduces flood risk to 333 homes and…
Posted on 6th February, 2026
by Charlotte Stone
Raindrops on a window overlooking a busy city street, illustrating how increasing rainfall is changing UK flood risk.

How Increasing Rainfall Is Changing Flood Risk in the UK

Flooding across the UK is becoming more frequent, more widespread and easier to trigger, and increasing rainfall is the reason. The shift is driven less by wilder storms than by a wetter atmosphere and wetter autumns and winters, which together…
Posted on 5th February, 2026
by Edward Bouët
Flood risk is rising at Britain’s most famous landmarks

Flood Risk at Britain’s Landmarks: What Six Famous Sites Reveal

Flood risk at the UK’s most famous landmarks is rising, and the pattern it reveals matters far beyond the sites themselves. In its Building Future Communities 2025 report, Aviva uses a handful of Britain’s best-known places — Hampton Court Palace,…
Posted on 4th February, 2026
by Jackie Stone
Aerial view of the houses at Clydach Terrace beside a river and woodland, illustrating managed retreat from flood risk.

Clydach Terrace, Ynysybwl: How 14 Flood-Prone Homes Fell Outside the Flood Defence System

Clydach Terrace in Ynysybwl, Rhondda Cynon Taf, is a row of terraced homes on the valley floor beside the Nant Clydach. On 2nd February 2026 the council's cabinet agreed to buy 14 of them for about £2.57 million, demolish them…
Posted on 3rd February, 2026
by Jackie Stone
Blue plaque recording the high water mark of the 1953 North Sea flood on a brick wall at Leigh-on-Sea, Essex.

Nine hours of warning: the 1953 North Sea flood and the failure that killed 307 people

The 1953 North Sea flood killed 307 people in England on the night of Saturday 31 January and the morning of Sunday 1 February. It remains the deadliest natural disaster in modern British history. Sea defences failed in 1,200 separate…
Posted on 31st January, 2026
by Edward Bouët
Man resting his head on a laptop keyboard in frustration, illustrating how a flood risk data delay slows planning.

Flood risk data delay slows planning and housing delivery

Yesterday, on 29th January 2026, updated surface water flood risk data was due to be published for use in development planning. Late in the day, it was confirmed that the release had been delayed, with no revised publication date and…
Posted on 30th January, 2026
by Edward Bouët
Storm Chandra flooding hits UK weeks after Storm Goretti

Storm Chandra flooding hits UK weeks after Storm Goretti

Storm Chandra is causing widespread flooding across the UK and Ireland, marking the second major flooding event of 2026 before the end of January. Flooding and disruption have continued into Wednesday, with impacts persisting across several regions. The storm follows…
Posted on 28th January, 2026
by Charlotte Stone
Aerial view of a new housing development under construction, the kind of major scheme the CIRIA SuDS Manual (C753) guides drainage design for.

The CIRIA SuDS Manual (C753): What It Is and How to Use It in 2026

The CIRIA SuDS Manual (C753) is the UK's principal design guide for sustainable drainage systems: 968 pages covering how SuDS should be planned, designed, built, operated and maintained. CIRIA published it in November 2015 to replace the original 2007 manual,…
Posted on 26th January, 2026
by Antony Rousou
Flooded field with a broken fence reflected in the water, illustrating why Lincolnshire is trialling new flood warnings.

Why Lincolnshire Is Trialling a New Approach to Flood Warnings

In parts of Lincolnshire, flooding is a familiar experience that does not always come with a warning. Streets flood, gardens fill, groundwater emerges, and yet many locations sit outside the areas where the national warning service is designed to operate.…
Posted on 23rd January, 2026
by Edward Bouët
Storm waves overtopping a coastal sea wall by seafront houses, the kind of tidal flood risk that climate change allowances assess.

Climate Change Allowances for Flood Risk Assessments: Which One Do You Use?

Climate change allowances are the uplift figures the Environment Agency expects you to build into a flood risk assessment so a development stays safe for its whole lifetime rather than only on the day it opens. There are four of…
Posted on 21st January, 2026
by Emma Jeffery
Two cars submerged in muddy flood water on a flooded UK road, showing the kind of flooding a flood risk assessment is required to address.

When Do You Need a Flood Risk Assessment (FRA)?

Do I need a flood risk assessment? For most people the answer turns on two things: where the site sits on the Environment Agency’s flood map, and what you plan to do with it. A flood risk assessment, or FRA,…
Posted on 19th January, 2026
by Emma Jeffery
Royal Courts of Justice entrance seen from below, illustrating the Gladman judgment on the Sequential Test.

What the Gladman Judgment Means for the Sequential Test

Flood risk, planning appeals and the High Court The High Court’s judgment in Gladman Developments Ltd v Secretary of State for Housing, Communities and Local Government and Lancaster City Council (15 January 2026) is an important decision on flood risk,…
Posted on 16th January, 2026
by Edward Bouët
Does flood risk affect house prices: floodwater covers a riverside park in front of a terrace of period brick houses.

Does Flood Risk Affect House Prices? How Much, and for How Long

Flood risk is priced into the UK housing market, and in June 2026 the shape of that pricing changed. Research published in Nature's Communications Earth & Environment tracked 27 million property sales across England over 28 years and found that…
Posted on 16th January, 2026
by Jackie Stone
Guildford Flood Alleviation Scheme: flood risk, history and consultation

Guildford Flood Alleviation Scheme: flood risk, defences and what happens next

The Guildford Flood Alleviation Scheme is a long-term project by the Environment Agency, Guildford Borough Council and Surrey County Council to reduce flood risk to Guildford town centre from the River Wey. It proposes more than two kilometres of new…
Posted on 14th January, 2026
by Freya Pott
Aerial view of a housing construction site beside a dual carriageway at Attleborough, illustrating construction stage flood risk.

Construction stage flood risk: the gap between planning permission and practical completion

Construction stage flood risk is the flood risk a development creates, or is exposed to, between the day permission is granted and the day the scheme is finished. It is the phase in which temporary access roads cross watercourses, ground…
Posted on 13th January, 2026
by Jesy Ferry
Prospective buyer studying estate agent window listings, the point to check flood risk before buying a property.

Flood risk before buying a property: how to check and understand it

Flood risk is one of the few things you can investigate properly before you commit to buying, and one of the most expensive to discover afterwards. To check flood risk before buying a house, start with the free government flood…
Posted on 12th January, 2026
by Jackie Stone
Flood Re scheme logo over a flooded field lined with bare poplar trees on a bright winter day.

What Is Flood Re? The Flood Re Scheme Explained

The Flood Re scheme is a UK government-backed reinsurance scheme that keeps home flood insurance available and affordable for households at higher flood risk. Set up under the Water Act 2014 and launched in April 2016, it lets insurers pass…
Posted on 7th January, 2026
by Jackie Stone
Abstract 3D data landscape in teal and purple, representing AI in flood risk management and the data behind flood prediction.

How AI Could Improve Flood Risk Management

Artificial intelligence is starting to reshape flood risk management, though not in the way the headlines suggest. AI in flood risk management works best as a support layer: it sharpens forecasting, widens warning coverage and speeds up the handling of…
Posted on 5th January, 2026
by Edward Bouët
Merry Christmas from all at Unda!

Merry Christmas 2025 from all at Unda!

We would like to thank our clients, colleagues and professional partners for working with us over the past year. We wish you a restful Christmas and a steady start to the year ahead. Merry Christmas from all at Unda!
Posted on 24th December, 2025
by Marketing Manager
Below standard flood defences on a seafront, with a broken concrete sea wall and shingle washed across the car park behind.

Below Standard Flood Defences: Protected on Paper, Vulnerable in Practice

Flood defence condition is measured against a target, not against whether a wall is still standing. On 1 April 2026 the Environment Agency reported that 93% of its flood risk assets in high consequence systems were in the required condition,…
Posted on 24th December, 2025
by Edward Bouët
The Whitchurch canal breach on the Llangollen Canal, with the embankment collapsed and a narrowboat dropped into the void.

Shropshire Canal Failure: What the Whitchurch Canal Breach Means for Flood Risk and Planning

A canal breach is the sudden failure of the bank or bed that holds a canal's water, and it matters for planning because most of Britain's canals sit above the land around them. When one gives way, the water does…
Posted on 23rd December, 2025
by Emma Jeffery
Flooding Across England and Wales Ahead of Christmas 2025

Flooding Across England and Wales Ahead of Christmas 2025

In the weeks leading up to Christmas 2025, large parts of England and Wales flooded repeatedly. It was not one storm. Rain fell on ground that was already full. In many places the water then sat there, long after the…
Posted on 22nd December, 2025
by Charlotte Stone
Unda Consulting, Oak Cottage

Unda Moves to New Offices in County Oak, Crawley

Unda has moved into new offices at Oak Cottage in County Oak, Crawley. The team is fully set up there, and the move changes nothing about how Unda handles flood risk assessments for planning, surface water drainage strategies or any…
Posted on 19th December, 2025
by Charlotte Stone
December 2025 NPPF Draft | Flood Risk and Sequential Test

December 2025 NPPF Draft | Flood Risk and Sequential Test

Update, 17 August 2026: the final Framework has now been published and replaces the December 2024 NPPF. This article is retained as a record of what the consultation draft proposed. For what the published version actually changed, read our full…
Posted on 18th December, 2025
by Jackie Stone
Soils, Flooding and Resilience | World Soil Day

Soils, Flooding and Resilience | World Soil Day

World Soil Day, observed each year on 5th December, highlights the critical importance of soils to environmental systems that are often taken for granted. Led by the UN Food and Agriculture Organization through the Global Soil Partnership, it focuses global…
Posted on 5th December, 2025
by Charlotte Stone
RNLI Flood Rescue and UK Emergency Response

Who Rescues You in a Flood? How England’s Flood Response Actually Works

When floodwater reaches the doorstep, flood rescue in England is carried out by whoever is closest, trained and available — usually the local fire and rescue service, supported by volunteer boat crews, Coastguard teams, the RNLI, mountain and lowland rescue…
Posted on 20th November, 2025
by Charlotte Stone
Flooded street in Wales with a submerged car and bilingual road signs, illustrating the Flood Map for Planning in Wales.

Flood Map for Planning Wales: Flood Zones Explained

The Flood Map for Planning Wales is the official map used to assess flood risk in the Welsh planning system. Produced by Natural Resources Wales (NRW), it shows where land is at risk of flooding from rivers, the sea, and…
Posted on 14th November, 2025
by Jackie Stone
Welsh Government building with its red bilingual sign, illustrating TAN 15 on flood risk and development in Wales.

TAN 15 Explained: Flood Risk and Development in Wales

Technical Advice Note 15 – Development, Flooding and Coastal Erosion (TAN 15) – is Welsh Government planning guidance that sets out how flood risk and coastal erosion must be addressed in the planning system in Wales. The current version came…
Posted on 12th November, 2025
by Jackie Stone
Resilience by Repetition: 25 Years on from the 2000 Severn Floods

Shrewsbury Floods, Ironbridge and Bewdley: What 25 Years of Severn Defences Changed

Shrewsbury floods because the town sits inside a loop of the River Severn, on ground the river has always used, at the foot of a catchment that gathers rain across mid Wales. Ironbridge and Bewdley flood for the same reason…
Posted on 5th November, 2025
by Emma Jeffery
York and the River Ouse Remember the Floods of 2000

York Flooding: Why the Ouse Rises, and What 25 Years of Defences Changed

York flooding is not a freak event. It is the predictable consequence of where the city was built: at the meeting point of two rivers, at the bottom of a catchment draining most of the Yorkshire Dales, on ground flat…
Posted on 5th November, 2025
by Jackie Stone
Runways Underwater: The 2000 Crawley and Gatwick Floods

Runways Underwater: The 2000 Crawley and Gatwick Floods

The Crawley and Gatwick floods of November 2000 saw the Gatwick Stream and the wider Upper Mole catchment overwhelm homes, roads and even the runways at one of the country's busiest airports. They were one local chapter of the wettest…
Posted on 4th November, 2025
by Edward Bouët
25 Years On: The Legacy of the Lewes Floods

25 Years On: The Legacy of the Lewes Floods

The Lewes floods of October 2000 were among the most severe England has seen in living memory. On 12 October 2000, after the wettest autumn on record, the River Ouse overwhelmed the town in a matter of hours, inundating 613…
Posted on 3rd November, 2025
by Ellen Webb
Who Is Responsible for Managing Flood Risk in England?

Who Is Responsible for Managing Flood Risk in England?

Flooding in England can happen anywhere — from rivers, the sea, surface water, groundwater, sewers or even small streams that overflow after heavy rain. Because these sources of flooding behave differently, no single organisation is responsible for everything. Instead, flood…
Posted on 31st October, 2025
by Jackie Stone
Loughborough Study Shows Sediment Ponds Aid Flood Control

Sediment ponds: what the Loughborough study shows

Sediment ponds are small excavated basins, often no bigger than five metres square, that hold back muddy runoff at the edge of a field so the soil it carries settles out before it reaches a ditch or a river. Research…
Posted on 31st October, 2025
by Charlotte Stone
Block paving being laid along a garden path, showing how paving over gardens replaces soil that would otherwise absorb rainfall.

Paving Over Gardens: Flood Risk and the Rules You Need to Know

Paving over gardens is one of the quiet drivers of urban flooding in the UK. When grass and planting are replaced with concrete, tarmac or block paving, rainwater can no longer soak into the ground. It runs off into drains…
Posted on 30th October, 2025
by Charlotte Stone
Flood Resilience in England: A Wake-Up Call

Flood Resilience in England: A Wake-Up Call

Flooding in England is no longer a localised hazard — it is a national systems challenge. The House of Commons Environmental Audit Committee’s latest report, Flood Resilience in England (HC 550, October 2025), delivers a blunt assessment: the country remains…
Posted on 29th October, 2025
by Edward Bouët
Electric car driving through deep muddy flood water, showing how to drive through flood water safely.

How to Drive Through Flood Water

Knowing how to drive through flood water safely comes down to one rule above all others: if you can avoid it, don't drive through it at all. The Environment Agency advises drivers not to enter water that is moving or…
Posted on 28th October, 2025
by Charlotte Stone
The River Arun reaching the sea at Littlehampton, in the district where the Arun SuDS design checklists set the drainage evidence bar.

Arun’s SuDS Design Checklists: From Outline Application to Occupation

The Arun SuDS design checklists are five separate documents, published by Arun District Council in October 2025, and between them they govern a scheme from its first outline drawing to the day someone moves in. They align the district with…
Posted on 27th October, 2025
by Antony Rousou
Wooden water butt collecting roof runoff from a downpipe in a garden, a simple example of rainwater harvesting.

Integrating Rainwater Harvesting into SuDS Design

Rainwater harvesting in SuDS design sits in an odd position. Collection for non-potable use is Priority 1 in the national discharge hierarchy, ahead of infiltration, a watercourse and any surface water or combined sewer. Yet on most planning applications the…
Posted on 24th October, 2025
by Antony Rousou
Green SuDS: Nature-Based Drainage in Modern Planning

Green SuDS: Nature-Based Drainage in Modern Planning

Green SuDS are nature-based drainage features — swales, rain gardens, basins, green roofs and wetlands — that manage rainwater using vegetation and soil rather than buried pipes and tanks. Across England's planning system they have become the preferred form of…
Posted on 22nd October, 2025
by Edward Bouët
NAFRA2 and Home Sales: Rising Flood Awareness

NAFRA2 and Home Sales: Rising Flood Awareness

When the Environment Agency released its latest National Assessment of Flood Risk for England (NAFRA2) in early 2025, the updated dataset immediately began reshaping how flood risk is understood — and, increasingly, how property is bought and sold. Many homeowners…
Posted on 20th October, 2025
by Antony Rousou
CIWEM logo over a fast-flowing stream beneath a stone arch bridge, for an article on the Chartered Institution of Water and Environmental Management.

What Is CIWEM? The Chartered Institution of Water and Environmental Management Explained

If you have ever read a flood risk assessment or a drainage strategy and seen the letters MCIWEM or C.WEM after a consultant’s name, you have already met CIWEM. It is the professional body that sits behind those letters, and…
Posted on 17th October, 2025
by Jackie Stone
Cover of the National Planning Policy Framework, the government document that sets NPPF flood risk policy for planning in England.

Planning for Flood Risk: The NPPF Explained

The NPPF is the National Planning Policy Framework: the government's planning policy for England, which councils apply when they decide planning applications and prepare local plans. The current Framework was published on 17 August 2026 and replaces every edition issued…
Posted on 16th October, 2025
by Edward Bouët
Defra flood risk management graphic: the Department for Environment, Food & Rural Affairs logo over an aerial view of a flooded river floodplain.

Defra’s Role in Flood Risk Management: Policy, Funding and Planning

The Department for Environment, Food and Rural Affairs (Defra) is the government department that leads flood risk management in England. It writes national flood policy, owns the legislation and decides how much public money goes into flood defences, and on…
Posted on 16th October, 2025
by Edward Bouët
Planning is falling behind flood risk, says Aviva

Planning is falling behind flood risk, says Aviva

Aviva’s Building future communities analysis presents a stark assessment of flood risk in England. By the middle of the century, millions more properties could be exposed to flooding, with risk increasingly driven by surface water flooding rather than rivers or…
Posted on 15th October, 2025
by Jackie Stone
Defra Confirms £10.5bn Flood Defence Funding Overhaul

Defra Confirms £10.5bn Flood Defence Funding Overhaul

In April, Defra’s consultation proposing a major overhaul of England’s flood funding system was launched, aiming to simplify access to investment and accelerate protection for communities most at risk. That consultation has now concluded, and the government has confirmed that…
Posted on 14th October, 2025
by Edward Bouët
Water pooled across an indoor tiled floor behind wet floor signs, the kind of damage an escape of water claim covers.

Flood or Escape of Water? How UK Insurers Tell the Difference

A burst pipe in the loft and a river in the living room can do much the same damage, and still be paid under different parts of the same home insurance policy. Escape of water is the insurance term for…
Posted on 13th October, 2025
by Jackie Stone
Cover of CIRIA's C823F guide promoting early SuDS planning, with an illustrated development showing a pond, swales and green open space.

Early SuDS Planning: CIRIA C823F and What the 2026 NPPF Now Requires

Early SuDS planning means settling the surface water question at land acquisition and site appraisal, before roads, levels and plot positions are fixed. Since 17 August 2026 that is no longer only good practice. CIRIA's guide Enabling development: Getting SuDS…
Posted on 6th October, 2025
by Ellen Webb
UK Tree Planting Shortfall Weakens Flood Resilience

Does Tree Planting Reduce Flood Risk? What the UK Evidence Actually Shows

Does tree planting reduce flood risk? Yes, but the size of the effect depends almost entirely on scale, and the honest answer changes depending on how far back you stand. Measure a woodland hillside against the grazed field next to…
Posted on 26th September, 2025
by Edward Bouët
September 2025 PPG Update: Flood Risk Sequential Test

PPG flood risk: what the September 2025 Sequential Test update changed

The PPG flood risk guidance changed on 17th September 2025, and the four paragraphs it rewrote decide how a Sequential Test gets scoped and evidenced today. The sequential approach now reads across every source of flooding, surface water included. A…
Posted on 22nd September, 2025
by Edward Bouët
TCPA Raises Alarm on the Sequential Test: How Valid Are Their Concerns?

TCPA Raises Alarm on the Sequential Test: How Valid Are Their Concerns?

In August 2025 the Town and Country Planning Association (TCPA) issued a strongly worded briefing note on the sequential test. The paper reflects growing unease that the cornerstone of flood risk planning policy is being eroded through recent appeal decisions.…
Posted on 12th September, 2025
by Edward Bouët
Severely depleted UK reservoir with wide exposed banks during drought, the parched conditions behind the floods in a drought paradox.

Floods in a Drought: Why Drought Causes Flooding in the UK

Floods in a drought sound like a contradiction. They are not. When soil has been baked hard for weeks it sheds rain rather than absorbing it, so one summer downpour can put water across roads and through doorways while rivers,…
Posted on 11th September, 2025
by Charlotte Stone
River in flood across a riverside quay in a historic town, with geese swimming in front of shops and townhouses.

Flood Map for Planning: What It Shows and How to Use It

The Flood Map for Planning is the Environment Agency's official online map of flood risk from rivers and the sea across England, used in the planning system to decide whether flooding needs to be assessed for a site. It is…
Posted on 29th August, 2025
by Edward Bouët
Flooded village street in England with a rescue dinghy, the river flooding that flood zones explained in this guide are meant to identify.

Flood Zones Explained: Zone 1, 2 and 3 (England)

Flood zones are how the planning system in England describes the chance of a site flooding from rivers or the sea. They sort land into Flood Zone 1, 2 or 3 (with Zone 3 split into 3a and 3b), from…
Posted on 28th August, 2025
by Edward Bouët
Flood History Declarations When Selling a Property

Declaring Flooding When Selling a House: TA6 Rules, Real Cases and How to Check

If a home you are selling has ever flooded, you have to say so. Declaring flooding when selling a house in England and Wales is part of answering the TA6 Property Information Form, which asks whether any part of the…
Posted on 27th August, 2025
by Edward Bouët
EA Flood Map for Planning: August 2025 Update

EA Flood Map for Planning: August 2025 Update

On the 27th August 2025, the Environment Agency (EA) will roll out changes to the Flood Map for Planning (FMfP). This update aims to make climate change flood risk data easier to use at the planning stage, while keeping the…
Posted on 15th August, 2025
by Edward Bouët
Can the Sequential Test Be Reformed to Unlock Homes?

Can the Sequential Test Be Reformed to Unlock Homes?

As appeals like Faversham and Yatton make clear, national policy on flood risk is straining under its own weight. The Sequential Test — originally designed to steer vulnerable development away from areas at highest flood risk — is now increasingly…
Posted on 25th July, 2025
by Edward Bouët
Ofwat Abolished: What IWC Report Means for Planning

Ofwat Abolished: What the Cunliffe Review Means for Planning

The Cunliffe review made 88 recommendations for the water sector in England and Wales, and the one everybody remembers is the abolition of Ofwat. Fourteen months on, the picture is more mixed than the headlines suggested. Government has accepted the…
Posted on 21st July, 2025
by Edward Bouët
Texas Flooding: UK Lessons in Risk and Resilience

Camp Mystic and the UK: Could a Flood Like Texas Happen Here?

The Camp Mystic flood of 4 July 2025 killed 28 people at a single riverside summer camp in the Texas Hill Country, 25 of them children. Two official investigations have since reported, and both reached the same uncomfortable conclusion: the…
Posted on 10th July, 2025
by Edward Bouët
What Is the Flood Forecasting Centre (FCC)?

Flood Forecasting Centre vs the Environment Agency: Who Forecasts, Who Warns

The Flood Forecasting Centre forecasts flooding. The Environment Agency warns the public about it. Two organisations, two jobs, and a boundary almost nobody outside the responder community can draw. It matters more than it sounds. A planning condition can hang…
Posted on 8th July, 2025
by Edward Bouët
Met Office logo over a weather chart of a deep low pressure system with isobars and fronts, illustrating Met Office flood management.

Met Office Flood Warnings: Who Actually Issues Them

The Met Office does not issue flood warnings. That one fact clears up most of the confusion behind the phrase, because a search for Met Office flood warnings almost always ends up somewhere else. The Environment Agency issues flood alerts…
Posted on 7th July, 2025
by Edward Bouët
Faversham Appeal Shifts Flood Risk Sequential Test Best Practice

Faversham Appeal Shifts Flood Risk Sequential Test Best Practice

A recent appeal decision (Ref: APP/V2255/W/24/3350524) has stirred interest across the planning and flood risk sectors. The case concerned an outline application for 250 homes on land at Ham Road, Faversham — partly at risk from tidal and surface water…
Posted on 3rd July, 2025
by Edward Bouët
Mayor of London Issues Urgent Basements Flash Flood Warning

Mayor of London Issues Urgent Basement Flash Flood Warning

As this year’s London Climate Action Week came to a close, the Mayor of London issued a direct and sobering warning to thousands of residents living in basement flats: be prepared for flash floods. As Sadiq Khan put it, “The…
Posted on 1st July, 2025
by Jackie Stone
Drainage field under construction, with perforated distribution pipes in gravel-filled trenches, sized using BS 6297 infiltration testing.

What is BS 6297 infiltration testing for foul drainage fields?

BS 6297 infiltration testing measures whether the ground on a site can absorb and treat effluent safely, and it is what decides whether a drainage field is a workable way to deal with foul drainage where there is no mains…
Posted on 26th June, 2025
by Ellen Webb
Understanding the 2025 National Standards for Sustainable Drainage Systems (SuDS)

National Standards for Sustainable Drainage Systems (SuDS): What They Require in 2026

The National Standards for Sustainable Drainage Systems are Defra's design rules for how surface water is managed on new development in England. Defra published them on 19 June 2025 and updated them on 30 July 2025, replacing the thin 2015…
Posted on 20th June, 2025
by Ellen Webb
Curved concrete sea defences at the foot of a coastal village, built to turn waves back and protect the homes above.

£7.9bn Flood Defence Programme: What the Money Actually Buys

The £7.9 billion flood defence programme is the ten-year capital settlement for flood and coastal erosion risk management in England. It was set at the June 2025 Spending Review, started on 1 April 2026 and runs to March 2036. Over…
Posted on 19th June, 2025
by Jackie Stone
Illustration of a winding watercourse with rocks, banks and trees, depicting riparian ownership of land beside a stream.

Riparian Rights and Ownership: Responsibilities and the Law in the UK

Riparian rights are the rights and duties that come with owning land beside, above or containing a watercourse, whether that is a river, a stream, a brook or a ditch. Unless your title deeds say otherwise, the law presumes you…
Posted on 6th June, 2025
by Jackie Stone
Defra Unveils Major Overhaul of Flood Funding System

Defra Unveils Major Overhaul of Flood Funding System

The UK is entering a pivotal phase in its approach to managing flood risk. On 3 June 2025, Minister Emma Hardy launched a major consultation at the Flood & Coast Conference, setting out the government's proposed reforms to the Flood…
Posted on 3rd June, 2025
by Edward Bouët
Thames Water Crisis: Sewage, Fines and Flood Risks

Thames Water Crisis 2026: Sewage, Capacity and Flood Risk by Area

The Thames Water crisis has moved a long way since the record fine of May 2025, and the part that matters most to anyone building in the Thames Valley is no longer the debt. It is capacity. Ofwat's investigation found…
Posted on 28th May, 2025
by Edward Bouët
Planning with EA Flood Risk Standing Advice

Planning with EA Flood Risk Standing Advice

The Environment Agency's flood risk standing advice is national guidance that lets a local planning authority in England decide a planning application on flood risk without consulting the Environment Agency case by case. Written out in full it is the…
Posted on 23rd May, 2025
by Emma Jeffery
What the 2025–30 London Surface Water Strategy Means for Planning

What the 2025–30 London Surface Water Strategy Means for Planning

As climate change accelerates and urban environments become denser, cities around the world face mounting challenges in managing water. Nowhere is this truer than in London, where the convergence of ageing infrastructure, rising population pressures, and increasingly erratic weather patterns…
Posted on 22nd May, 2025
by Antony Rousou
Hosepipe Bans Loom Without Smarter Planning

Hosepipe Bans: Rules, Exemptions and Why They Happen

Hosepipe bans happen when a water company decides it is facing a serious shortage of water for distribution and uses a statutory power to prohibit a list of outdoor uses. The trigger is rarely one dry month. It is the…
Posted on 19th May, 2025
by Edward Bouët
Oxford Flood Alleviation Scheme (OFAS) Approved

Oxford Flood Alleviation Scheme (OFAS) Approved

The Oxford Flood Alleviation Scheme (OFAS) is a £176 million flood defence project, led by the Environment Agency, that will reduce flood risk to more than 1,600 homes and businesses across Oxford and the surrounding villages. At its heart is…
Posted on 16th May, 2025
by Edward Bouët
VE Day and the Weaponisation of Flooding in the Netherlands

VE Day and the Weaponisation of Flooding in the Netherlands

In the closing weeks of the Second World War, as Nazi Germany faced certain defeat, its occupying forces in the Netherlands turned water against the people it had once kept safe. The deliberate breaching of dikes and the release of…
Posted on 8th May, 2025
by Edward Bouët
New TAN15 2025: Flood & Planning Policy Update

New TAN15 2025: Flood & Planning Policy Update

The new TAN15 took effect on 31 March 2025, and it is the largest change to flood risk planning in Wales in more than twenty years. Technical Advice Note 15: Development, Flooding and Coastal Erosion replaced an edition written in…
Posted on 2nd April, 2025
by Emma Jeffery
Sequential Test Failed, Appeal Allowed: What Yatton Means for Planning

Sequential Test Failed, Appeal Allowed: What Yatton Means for Planning

A recent planning appeal decision in Yatton provides an insightful take on how the Sequential and Exception Tests are interpreted and applied within flood risk planning policy. This appeal, concerning the proposed development of a residential scheme on land south…
Posted on 28th March, 2025
by Edward Bouët
What developers and planners need to know about the 2025 EA Flood Map update, including new data, zones, and guidance.

EA Flood Map for Planning: 2025 Update Explained

On 25th March 2025, the Environment Agency (EA) launched a major update to its Flood Map for Planning (FMfP), marking a pivotal shift in how flood risk is represented for the planning system in England. This update integrates findings from…
Posted on 27th March, 2025
by Edward Bouët
Ordinary Watercourse Consent (OWC) Explained

Ordinary Watercourse Consent (OWC): The Complete Guide

Ordinary watercourse consent (OWC) is the written permission you need under Section 23 of the Land Drainage Act 1991 before carrying out any work that would obstruct or alter the flow of an ordinary watercourse: a stream, ditch, culvert or…
Posted on 28th February, 2025
by Jackie Stone
Concrete marker post labelled septic tank on a grass verge, marking a private system subject to septic tank regulations.

Septic tank regulations in England: the General Binding Rules in 2026

The General Binding Rules are the statutory conditions that let a septic tank or a small sewage treatment plant discharge legally in England without an environmental permit. There are 23 of them. Meet every rule that applies to your discharge…
Posted on 28th February, 2025
by Antony Rousou
How to Maintain Your Drains to Prevent Surface Water Flooding

What Is a Surface Water Drain? Where Yours Goes and Who Owns It

A surface water drain carries rainwater away from your roof, driveway and garden. It is a separate system from the foul drain that takes waste from your sinks and toilet, and it usually ends in one of three places: a…
Posted on 26th February, 2025
by Edward Bouët
Foul, Surface & Combined Sewers: What to Know

Foul, Surface Water and Combined Sewers: How to Tell Them Apart

A foul sewer carries wastewater to treatment. A surface water sewer carries rainwater to a watercourse or an outfall. A combined sewer carries both in one pipe, and spills to a watercourse through a storm overflow when it fills. Those…
Posted on 25th February, 2025
by Edward Bouët
Tideway logo over the curved, segment-lined interior of a large sewer tunnel, illustrating the Thames Tideway Tunnel in London.

London’s Super Sewer in Numbers: The Tideway Tunnel

London's super sewer captured 18.4 million tonnes of sewage in its first full year of operation, against a pre-tunnel baseline of roughly 39 million tonnes reaching the tidal Thames in an average year. The Thames Tideway Tunnel runs 25 kilometres…
Posted on 17th February, 2025
by Jackie Stone
The Thames Barrier on the River Thames near Woolwich, with its silver piers and a raised steel gate against the east London skyline.

Thames Barrier: Closures, Cost and Its Future

The Thames Barrier has closed 221 times for flood defence since it became operational in 1982, a figure the Environment Agency states as correct at 17 November 2025. Of those Thames Barrier closures, 119 held back a tidal surge from…
Posted on 14th February, 2025
by Antony Rousou
Natural Flood Management: EA Research Deep Dive & Analysis

Natural Flood Management: EA Research Deep Dive & Analysis

Natural flood management (NFM) does work, but the honest answer is more useful than a simple yes. The Environment Agency's latest evidence shows that measures which slow, store and filter water across a catchment can measurably lower flood peaks, especially…
Posted on 13th February, 2025
by Edward Bouët
NaFRA2 Guidance: Flood Map for Planning Updates

NaFRA2 Guidance: Flood Map for Planning Updates

Understanding NaFRA2 and Its Impact on Flood Risk Assessments The Environment Agency (EA) has today provided new guidance on how NaFRA2 data will shape the future of the Flood Map for Planning. These updates will significantly influence local planning policies,…
Posted on 11th February, 2025
by Emma Jeffery
UK Sees Record Flood Insurance Claims in 2024 as Extreme Weather Intensifies

UK flood insurance claims: the payouts, the timescales and the trend behind them

UK flood insurance claims reached £312 million in 2025, a 38 per cent rise in a single year, and the average payout to a flooded household hit £30,000, up 60 per cent. Those are the Association of British Insurers' own…
Posted on 11th February, 2025
by Jackie Stone
UK Housing Plans and Flood Risk: Striking the Right Balance

New Homes in Flood Risk Areas: What the Numbers Actually Say

About one in nine new homes built in England between 2022 and 2024 stands in an area at medium or high risk of flooding. The government says more than 99% of new homes proposed in planning applications comply with Environment…
Posted on 10th February, 2025
by Edward Bouët
£2bn Boost for UK Flood Defences to Combat Rising Risks

£2bn Boost for UK Flood Defences to Combat Rising Risks

The UK government has pledged an additional £250 million in flood defence funding, bringing the total investment to £2.65 billion over the next two years. The announcement follows a series of devastating storms and widespread flooding, with the government seeking…
Posted on 5th February, 2025
by Edward Bouët
Natural Flood Management: Harnessing Nature to Combat Flood Risks

Natural Flood Management Schemes in the UK: How Real Projects Slow the Flow

Natural flood management schemes use woodland, wetlands, leaky dams and better-managed soils to slow and store rainwater across a catchment, taking the edge off flood peaks downstream. Across the UK, councils, rivers trusts and landowners now run dozens of these…
Posted on 3rd February, 2025
by Edward Bouët
The new National Flood Risk Assessment (NaFRA2) is a revolutionary update that delivers enhanced flood modelling, high-resolution mapping, and improved climate change projections. Whether you're a homeowner, business owner, or policymaker, understanding flood risk is crucial for planning and resilience.

NaFRA2 Explained: What England’s National Flood Risk Assessment Found

NaFRA2 is the Environment Agency's new National Assessment of Flood Risk for England. Published in December 2024, it found that around 6.3 million homes and businesses are in areas at risk of flooding from rivers, the sea or surface water.…
Posted on 28th January, 2025
by Emma Jeffery
UK Braces for Flooding as Storm Éowyn Brings Heavy Rain and Strong Winds

UK Braces for Flooding as Storm Éowyn Brings Heavy Rain and Strong Winds

Dozens of flood warnings and alerts have been issued across the UK as severe weather batters the country. Storm Éowyn is bringing heavy rain and destructive winds, increasing the risk of flooding in multiple regions. At the time of writing,…
Posted on 24th January, 2025
by Edward Bouët
Floodwater covering a historic riverside street, the kind of event the Flood and Water Management Act 2010 was written to answer.

Flood and Water Management Act 2010: What’s in Force

The Flood and Water Management Act 2010 (FWMA) is the law that governs how flood risk is managed in England and Wales. It received Royal Assent on 8 April 2010, made county and unitary councils responsible for local flooding, gave…
Posted on 6th January, 2025
by Edward Bouët
Pitt Review Deep Dive: Impact, Legacy, and Gaps

The Pitt Review: impact, legacy and the gaps that remain

The 2007 floods turned the wettest summer on record into the most destructive inland flooding Britain had seen in modern times. Thirteen people died, more than 55,000 properties went under, around 7,000 people were rescued, and the bill came to…
Posted on 3rd January, 2025
by Edward Bouët
Flood Return Periods & Annual Probability Explained

Flood Return Periods & Annual Probability Explained

A flood return period is the average length of time between floods of a given size at a given place. That sounds like a timetable, and it is not one. A "1-in-100-year flood" does not arrive once a century: it…
Posted on 20th December, 2024
by Edward Bouët
What are the Sequential and Exception Tests?

The Sequential and Exception Tests Explained (2026 Update)

Updated 17 August 2026. This guide has been rewritten for the new National Planning Policy Framework, which the Government published on 17 August 2026. The new Framework replaced the December 2024 version and changed how the sequential and exception tests…
Posted on 16th December, 2024
by Edward Bouët
Mini-excavator digging a soakaway trial pit in soil for BRE365 infiltration testing on a development site.

What is BRE365 Infiltration Testing (Soakaway Design)?

BRE365 infiltration testing is the in-ground test that measures how fast your site's soil can absorb surface water, so you can prove a soakaway will work and size it correctly. It follows BRE Digest 365, the standard UK method for…
Posted on 2nd December, 2024
by Edward Bouët
Flood Modelling Software: Tools & Techniques Guide

Flood Modelling Software Explained: 1D, 2D and Coupled Models

Flood modelling software solves the equations that describe how water moves, then reports the answer as levels, depths, velocities and extents. Which package is used matters far less than how many dimensions the model solves in: one, two, or the…
Posted on 20th November, 2024
by Emma Jeffery
Topographical Surveys for FRA & SuDS: When Are They Needed?

Topographical Surveys for FRA & SuDS: When Are They Needed?

A topographical survey is a measured land survey that records a site's exact levels, contours, features and existing drainage. For a flood risk assessment or a SuDS drainage design, it is the ground truth everything else sits on. You usually…
Posted on 18th November, 2024
by Emma Jeffery
LiDAR Data for Flood Risk & Drainage Planning Explained

LiDAR Data in the UK: A Complete Guide for Flood Risk and Drainage

LiDAR data in the UK is free, national in coverage, and more widely misunderstood than any other dataset in flood risk assessment and drainage strategy practice. The Environment Agency publishes elevation models covering roughly 99% of England under the Open…
Posted on 15th November, 2024
by Freya Pott
What is GIS? A Key Tool for Flood Risk, Modelling & SuDS Design

What is GIS? A UK Guide for Flood Risk and Drainage

GIS stands for geographic information system. It is software that holds map features and the data attached to them together, so that questions about a place can be answered by analysis instead of by eye. Anything with a location can…
Posted on 8th November, 2024
by Antony Rousou
Level-for-Level Compensatory Flood Storage Explained

Compensatory flood storage explained: level for level design for planning

Posted on 1st November, 2024
by Edward Bouët
Flood Risk Activity Permits (FRAP) Explained

Flood Risk Activity Permits (FRAP): When You Need One, and When You Don’t

A flood risk activity permit (FRAP) is the environmental permit you need before working on, under, over or near a main river, a flood defence, a sea defence or a floodplain in England. The Environment Agency issues it under the…
Posted on 6th September, 2024
by Edward Bouët
Understanding Main Rivers & Ordinary Watercourses

Main Rivers and Ordinary Watercourses: A Guide for Planning

Every river, stream, brook and ditch in England and Wales is legally either a main river or an ordinary watercourse, and the difference decides who regulates it, who maintains it, and whose consent you need before you build near it.…
Posted on 5th September, 2024
by Edward Bouët
Water Authorities: Flood Risk, Drainage & Planning

Water Companies and the Planning Process: A Developer’s Guide

Water companies and the planning process are closely tied, even though the water company rarely appears on a decision notice. When you develop a site, your regional water and sewerage company is the body that confirms whether the network can…
Posted on 2nd September, 2024
by Edward Bouët
Local Planning Authorities (LPA): Flood and SuDS

What Is a Local Planning Authority (LPA)? A Guide for Developers

A local planning authority (LPA) is the council responsible for deciding planning applications in its area and for shaping how land is used and developed. Almost every development, from a single-storey extension to a housing scheme, passes through an LPA…
Posted on 30th August, 2024
by Edward Bouët
Natural Resources Wales logo over an aerial view of a flooded river valley, with fields and trees under brown floodwater.

Natural Resources Wales (NRW): Its Role in Flood Risk and Planning

Natural Resources Wales (NRW) is the public body that manages flood risk from rivers, the sea and reservoirs in Wales, and the organisation a local planning authority must consult when a development site sits in a flood zone. It does…
Posted on 29th August, 2024
by Emma Jeffery
Environment Agency logo over an aerial view of a flooded river floodplain, for a guide to Environment Agency planning.

The Environment Agency in Planning: Its Flood Risk Role Explained

The Environment Agency (EA) is the statutory adviser on flood risk from rivers, the sea and reservoirs in England's planning system. It does not grant or refuse permission; that decision belongs to the local planning authority, which weighs the Agency's…
Posted on 28th August, 2024
by Edward Bouët
Why Internal Drainage Boards (IDBs) Matter for Planning

Internal Drainage Boards (IDBs): what they do and why they matter for planning

An internal drainage board, usually shortened to IDB, is an independent public body that manages water levels and land drainage across a defined low-lying area where gravity drainage alone will not do the job. England has 112 of them, covering…
Posted on 27th August, 2024
by Ellen Webb
Sustainable drainage swale beside new-build housing, the kind of major scheme a lead local flood authority reviews.

Lead Local Flood Authority (LLFA): What It Is and Which Is Yours

A Lead Local Flood Authority (LLFA) is the county council or unitary authority responsible for managing local flood risk across its area: surface water, groundwater and ordinary watercourses. There are 153 of them in England. On major planning applications the…
Posted on 26th August, 2024
by Edward Bouët
What Are Strategic Flood Risk Assessments (SFRAs)?

What Is a Strategic Flood Risk Assessment (SFRA)?

A strategic flood risk assessment (SFRA) is the flood risk evidence base a local planning authority produces for its whole area, covering every source of flooding, now and under climate change. Every local planning authority in England has to prepare…
Posted on 23rd August, 2024
by Edward Bouët
The Boscastle Flood: 20 Years On

Boscastle Flood 2004: Causes, Impacts and What It Changed

On Monday 16 August 2004 a line of thunderstorms stalled over the moors above Boscastle and put more than 180 mm of rain into a catchment of barely 20 square kilometres. The Boscastle flood that followed destroyed four properties, flooded…
Posted on 16th August, 2024
by Emma Jeffery
EA Flood Map Challenge: What You Need to Know

How to Challenge the Environment Agency Flood Map

There is no form. If you want to challenge the Environment Agency flood map in England, the first thing to understand is that the Environment Agency publishes no procedure for doing it. There is no application route, no evidence checklist…
Posted on 3rd June, 2024
by Emma Jeffery
Flat illustration of a hand holding a house above rising flood water, a visual for flood risk and mortgage lending in the UK.

Can You Get a Mortgage on a Flood-Risk Property? UK Lending Guide (2026)

Yes — you can usually still get a mortgage on a flood-risk property. What decides it is the lender, whether the home can be insured affordably, and the quality of the evidence you put in front of them. Lenders have…
Posted on 30th April, 2024
by Jackie Stone
Applying the Sequential Test Post-Mead: A Guide for Planning Professionals

Applying the Sequential Test Post-Mead: A Guide for Planning Professionals

A recent decision of the High Court, upheld by the Court of Appeal in Mead Realisations Ltd v Secretary of State for Levelling Up, Housing and Communities [2024] EWHC 279, has clarified several key aspects of national planning policy relating…
Posted on 20th February, 2024
by Edward Bouët
Floodwater covering land beside Rotherham United's New York Stadium, showing flood risk at football stadiums

Which Football Stadiums Are at Risk of Flooding? The 2026 Picture

Two separate studies have counted the football stadiums at risk of flooding in England, and they disagree. Research for the Rapid Transition Alliance put 23 of the 92 league grounds in line for partial or total flooding every season by…
Posted on 30th November, 2023
by Matthew Rousou
The New TAN15: A Policy U-Turn with Lasting Implications for Flood Risk Management in Wales

The New TAN15: A Policy U-Turn with Lasting Implications for Flood Risk Management in Wales

When the Welsh Government announced plans to overhaul Technical Advice Note 15 (TAN15), it signalled a bold shift towards more stringent flood risk management in Wales. Designed to replace the 2004 TAN15 guidance, the new TAN15 aimed to integrate updated…
Posted on 22nd November, 2023
by Emma Jeffery
National Audit Office logo over a concrete flood wall on a grassed embankment, illustrating the NAO review of England's flood defences.

England’s flood defences: what the NAO found, and what happened next

England's flood defences were the subject of a National Audit Office report that found the country spending more on flood protection than at any point in its history, and still on course to protect far fewer homes than it had…
Posted on 16th November, 2023
by Edward Bouët
Car submerged in muddy floodwater on a village high street during the Great Flood of 1968 in the Bristol area.

The Great Flood of 1968: what two floods taught UK flood risk practice

The Great Flood of 1968 is really two floods. In July, a single night of rain over the Mendips tore bridges out of the Chew Valley and killed seven people. Ten weeks later, in the middle of September, much of…
Posted on 14th September, 2023
by Matthew Rousou
A man cleaning up after a flood wades through floodwater in an office, rescuing files and paperwork from the rising water.

What to Do After a Flood: A UK Recovery Guide

Knowing what to do after a flood comes down to sequence. Make the building safe, record the damage for your insurer, get the water and silt out inside 24 to 48 hours, strip out and disinfect over the following weeks,…
Posted on 23rd August, 2019
by Jackie Stone
Eurasian beaver feeding among willow at a river's edge, illustrating the link between beavers and flooding.

Beavers and Flood Risk: What Landowners and Developers Need to Know

Beavers and flood risk stopped being a curiosity the moment the law changed. England has had a licensed route to release beavers into the wild since February 2025, three projects are now running, and Natural England is working with around…
Posted on 19th February, 2018
by Thomas Smith
A dark shelf cloud and bands of rain sweeping over a UK town, the kind of sky a weather bomb brings.

What Is a Weather Bomb? Explosive Cyclogenesis Explained

A weather bomb is the informal name for a storm whose central pressure drops by at least 24 millibars in 24 hours, a process meteorologists call explosive cyclogenesis. The result is a deep, fast-developing area of low pressure that brings…
Posted on 22nd January, 2018
by Jackie Stone
Festival flooding at a UK campsite, with tents part-submerged in muddy surface water after heavy rain

Does Glastonbury flood? Why Worthy Farm turns to mud

Does Glastonbury flood? Yes, though almost never because a river burst its banks. Worthy Farm sits in a shallow valley on clay with a watercourse through the middle, and what turns the site to mud is rain arriving faster than…
Posted on 22nd June, 2017
by Charlotte Stone
The first of the UK's amphibious houses: Formosa, beside the River Thames near Marlow, designed to float in its dock during floods

Amphibious houses in the UK: can you get one approved?

An amphibious house sits on ordinary foundations for most of its life. When floodwater arrives it rises inside a purpose-built dock and floats, held straight by vertical guide posts, then settles back as the water drops. Nobody moves out. Britain…
Posted on 1st March, 2017
by Jackie Stone
Geological map of areas affected by groundwater flooding across southern England, with affected chalk villages labelled.

Communities Affected by Groundwater Flooding in the UK

Groundwater flooding is not spread evenly across the country. The areas affected by groundwater flooding cluster in a narrow band of communities sitting on or just downstream of the Chalk, and the same villages tend to flood again and again:…
Posted on 29th September, 2015
by Steve Buss
Cars submerged on a flooded UK town street, showing why knowing how to prepare for a flood can reduce damage to homes.

How to protect your home from flooding: a UK homeowner’s guide

You cannot stop a river rising or a storm drain backing up. What you can decide is how much of that water reaches your rooms, and how much it costs you when it does. Knowing how to protect your home…
Posted on 25th September, 2015
by Jackie Stone
Flooded low-lying fields beside dry higher farmland, showing why building on floodplains is tightly controlled.

Building on Floodplains: A Developer’s Guide to the 2026 Rules

Building on floodplains is not banned in England, but whether a scheme gets consent comes down to three things: the flood zone the land sits in, the type of development proposed, and the strength of the flood risk evidence submitted…
Posted on 18th September, 2015
by Jackie Stone