Flood Risk Assessment in Hull

Few cities in Britain live as closely with water as Hull. It sits where the River Hull meets the Humber estuary, on reclaimed land that lies largely below the level of the high tide, and almost every plot within it carries some degree of flood risk. A flood risk assessment in Hull is how a developer, homeowner or business shows that a site can be used safely in that setting, and how a planning application gets through a process that here treats flooding as the defining constraint.

Unda prepares flood risk assessments in Hull for planning, for property purchase, for mortgage and insurance, and for BREEAM, along with the sequential and exception tests and the surface-water drainage strategies (SuDS) that Hull schemes so often need. We assess every source that matters in the city: the tidal Humber, the River Hull, surface water and groundwater. We then deal directly with the Environment Agency, Hull City Council and Yorkshire Water on your behalf, guiding architects, planning consultants, developers and landowners through to approval. Hull is part of our wider work on flood risk across Yorkshire.

If you want a quote or need to talk a Hull site through, contact one of our experienced flood risk consultants on 01293 214444.

Flood risk assessment in Hull at a glance

• Around 90% of Hull lies below high-tide level. The city is built on reclaimed estuary land, much of it roughly two metres below the level the Humber reaches on a spring tide.
• Close to 98% of the city is in a flood risk area. That gives Hull the second-highest number of properties at risk of flooding of any urban area in the UK, after London, with around 100,000 at risk in the most extreme events.
• The 2007 floods hit roughly 8,600 homes and 1,300 businesses. Surface water, not a river or the sea, overwhelmed the drains, and it remains the city's defining flood event.
• Most of Hull sits in Flood Zone 3. The highest-probability zone covers the great majority of the city, so the sequential and exception tests are part of everyday development here.

Check flood risk at your Hull site

Hull is outlined below. Screen any postcode in the city against Environment Agency data for rivers and the sea, surface water and the planning flood zones, with a climate outlook to 2125. It is an indicative first pass, not a substitute for a site-specific flood risk assessment.

Where Hull's flood risk comes from

Hull faces flooding from four directions at once. The Humber can push saltwater up against the city on a tidal surge; the River Hull drains a large rural catchment to the north and runs through the middle of the city behind defences; rainfall that cannot soak into the low, flat ground becomes surface water; and a high water table means groundwater is never far below the surface. Most Hull sites face more than one of these at the same time, which is why a desktop map rarely satisfies a planning officer on its own.

The reason the city is so exposed is its geography. Hull grew on reclaimed estuary land at the mouth of the River Hull, with around 90% of it lying below the level of a high spring tide and much of the centre roughly two metres below it. Water does not drain away under gravity here; large parts of the city are kept dry by pumping. That single fact, a city living below the tide, shapes every flood risk assessment for planning prepared within it.

Knowing which of these drives the risk on a given plot, and how the sources interact, is the heart of a credible assessment. Our reports draw out tidal, fluvial, surface water and groundwater risk separately, then show how the proposed development responds to each.

Hull's history of flooding

Hull's flood record is the clearest evidence of how its risk behaves, and planning officers expect an assessment to engage with it. The city has been flooded by rain from above and by the sea from the estuary within living memory, and each event reshaped how development is now assessed.

• June 2007 — surface water. Exceptional rainfall, with over 100mm in 24 hours on 25 June, overwhelmed the drains. Around 8,600 homes and 1,300 businesses flooded, 91 of the city's 99 schools were damaged, some 20,000 people were affected and one man died. It fed directly into the national Pitt Review.
• December 2013 — tidal surge. A North Sea surge on 5 December drove the Humber to a record 5.8m at Hull, the worst tidal flooding in the region since 1953. Around 150 homes and over 100 businesses flooded in the city, with English Street, Victoria Dock and Hessle Road among the areas hit.
• 1969 — the trigger for the barrier. Tidal flooding in the late 1960s led to the River Hull Tidal Surge Barrier, completed in 1980, which now protects around 17,000 homes and businesses by closing off the river mouth during a surge.

The 2007 floods were caused by rain that could not drain away, not by a river bursting its banks, which is why surface water is treated so seriously in every Hull assessment.

Which flood zone is Hull in, and who is your Lead Local Flood Authority?

The great majority of Hull lies in Flood Zone 3, the Environment Agency's highest-probability zone, because the land sits below the tidal level of the Humber. Because so much of the city shares that single classification, Hull City Council's Strategic Flood Risk Assessment refines Flood Zone 3 into sub-areas so that planners can tell genuinely higher-risk land from the rest. Establishing where your site sits within that refined picture is usually the first job of an assessment.

Hull City Council is the Lead Local Flood Authority (LLFA) for the city, a unitary authority responsible for managing local flood risk — surface water, groundwater and ordinary watercourses — while the Environment Agency leads on the River Hull and the tidal Humber. The council sets out how it manages that risk in its Local Flood Risk Management Strategy and provides standing advice for developers. Knowing what each body expects, and getting drainage right early, is what keeps a Hull application moving.

• Lead Local Flood Authority. Hull City Council manages surface water, groundwater and ordinary watercourses, and is a statutory consultee on surface water drainage for major development. See the council's flooding and planning guidance.
• Local Flood Risk Management Strategy. The council's strategy for 2022–2028 sets out current risk in the city and how it will be managed.
• Strategic Flood Risk Assessment. The SFRA refines Flood Zone 3 across the city and underpins the flood policies in the Local Plan — the evidence base your assessment has to align with. Read more on how SFRAs work.
• Sustainable drainage is expected. The council promotes SuDS on major applications — but with a twist that matters in Hull.
• Infiltration usually does not work here. The high water table and low-permeability ground mean soakaways are rarely viable, so drainage tends to rely on above-ground storage and a controlled, often pumped, discharge rather than letting water soak away.

The defences also create a trap for the unwary. Because the Flood Map for Planning is drawn as if the tidal barrier and raised banks were not there, a well-defended Hull site can still sit firmly in Flood Zone 3 — a point we explain in why a defended site stays in a flood zone. Planning policy requires the residual risk, if a defence is overtopped or fails, to be assessed for the lifetime of the development.

Developing in Flood Zone 3: the sequential and exception tests in Hull

Because almost all of Hull lies in Flood Zone 3, the national policy tests that steer development away from flood risk come up on most schemes here. A sequential test asks whether the development could go on lower-risk land elsewhere; an exception test then asks whether the wider benefits outweigh the risk and whether the site can be made safe without increasing flooding elsewhere. In a city built almost entirely on Flood Zone 3 land, that is a familiar hurdle rather than a rare one.

Hull is largely a regeneration city. Much of its development is brownfield — city-centre renewal, the Fruit Market and marina, housing on previously used land, and employment sites around the port and the Humber energy cluster — rather than greenfield expansion. That makes the planning argument winnable: there is often a strong case that a regeneration site is the right place even though it sits in Flood Zone 3, provided the assessment defines the area of search sensibly and demonstrates the scheme is safe for its lifetime. Recent decisions, including those we discuss in our guide to the sequential test, show why getting that argument right at the application stage matters.

• Define the area of search well. A search area that reflects the scheme's purpose and catchment is what makes a sequential test defensible in a place where lower-risk land is scarce.
• Use modelling where the maps fall short. On estuary-front and riverside sites, hydraulic and tidal modelling can establish actual flood levels and the headroom your floor levels need.
• Design safe access and floor levels. Finished floor levels set above the modelled flood level, plus safe access and egress, are usually central to passing the exception test on a Hull site.

How Unda helps with flood risk in Hull

We are experts on Hull's flooding, not a general practice that treats it as just another postcode. We know the city sits below the tide, that surface water and groundwater do as much damage here as the rivers, and that a credible report has to reckon with the 2007 and 2013 events rather than ignore them. Every assessment is evidence-led, signed off by a senior flood risk consultant, and written to be approved first time and to stand up if the Environment Agency or the council asks questions.

That means a report that engages with the real local picture: the right sources assessed, the residual risk behind the defences spelled out, drainage that suits low, wet ground, and mitigation a planning officer in Hull will recognise as proportionate. We have worked across the wider region for years and bring that experience to every Hull instruction. You can read more about our flood risk consultants or about Unda.

Flood risk assessments for every situation in Hull

People need a flood risk assessment or a drainage strategy in Hull for many reasons, and we prepare each of them to the same standard. Whatever has prompted your enquiry, we can tell you quickly what is needed and what it will cost.

• Flood risk assessment for planning. The site-specific report submitted with a planning application to show the development is safe and does not increase flood risk elsewhere. See FRA for planning and our NPPF guidance.
• Flood risk survey for property purchase. An independent assessment for buyers, lenders and conveyancers when a search flags flood risk on a Hull property — our homebuyer flood risk survey.
• Flood risk assessment for insurance. A property-level report for owners facing raised premiums, restricted cover or a refusal — our FRA for insurance.
• Flood risk assessment for BREEAM. An assessment structured around BREEAM Pol 03 for project teams pursuing certification — our FRA for BREEAM.
• Sequential and exception tests. The locational policy reports that so many Flood Zone 3 schemes in Hull require — our sequential and exception test service.
• Surface-water drainage strategy (SuDS). A strategy showing how runoff is managed within the required discharge rate — our drainage strategy and SuDS service, with discharge of drainage conditions and preliminary drainage design where needed.
• Groundwater assessment. A focused look at the high Hull water table as a source of flood risk and a constraint on soakaways and basements — our groundwater flood risk service.
• Flood modelling. Hydraulic and tidal modelling for estuary-front and riverside sites where national maps are not enough — our flood modelling service.

Before commissioning a report, you can use our free tools to get an early read on a Hull site: the Flood Risk Map for a postcode screening, the Live River Levels Map for nearby gauges, the Ground Conditions checker for whether a soakaway is worth pursuing, and our drainage calculators and BRE 365 infiltration calculator for a first-pass drainage sum.

Local flood risk management and emergency contacts in Hull

Several bodies share responsibility for flood risk in Hull. The list below is a starting point for developers, homeowners and businesses who need to report flooding, sign up for warnings or reach the right team in an emergency.

• In a flooding emergency, call 999. Use 105 to report or check a power cut. Call Floodline on 0345 988 1188 for current flood warnings and advice.
• Sign up for flood warnings. Register a Hull property for free Environment Agency flood warnings covering the River Hull and Humber.
• Living With Water. Hull City Council, the Environment Agency, Yorkshire Water and partners run the Living With Water partnership, behind much of the city's recent flood resilience work.
• Defences worth knowing. The 42 million pound Humber Hull Frontage scheme now better protects around 113,000 properties along the estuary — see the Environment Agency announcement.

Flood risk assessment in Hull: frequently asked questions