Flood Risk Assessment in Ware

A flood risk assessment in Ware begins with the River Lea, which runs through the south of the town as the Lee Navigation, past the backs of the High Street and the old maltings at Broadmeads, on its way down to Hardmead and Stanstead Abbotts. Its flood zones cover the low streets between Priory Street and Amwell End, while the Chalk under the valley and the slopes that drain towards London Road add groundwater and surface water to the river risk. For sites in Ware we prepare flood risk assessments for planning, purchase, mortgage and insurance, along with sequential and exception tests and surface water drainage strategies.

Ware, Hertfordshire, is taken here as the built-up area the Office for National Statistics draws: the centre around the High Street, Baldock Street and Amwell End, Broadmeads and Crane Mead by the river, and Kingshill, Musley Hill and the estates up the slope to the north, all in the SG12 postcode district. Great Amwell, St Margarets and Stanstead Abbotts downstream, and Wareside on the River Ash, are separate villages outside that outline, but they share the town's river, council and flood evidence, so they appear here too.

Every flood defence East Hertfordshire's 2016 flood study lists in Ware, about 3.9 km of embankment along the Lea and the Stanstead Mill Stream and a 127 m wall, is privately maintained, and the wall was built to hold back only a two-year flood.

For a first view on an address in Ware, ring 01293 214444 or email enquiries@unda.co.uk.

Which streets in Ware sit in the Lea's flood zones?

Most of the river flood risk in Ware comes from the Lea, which the Environment Agency and the navigation spell Lee. East Hertfordshire's 2016 Level 1 and 2 SFRA named the parts of the town its Flood Zones 2 and 3 reach, and the council's September 2026 Level 1 SFRA, which now replaces that study for plan-making, still puts most of the district's river risk on the Lea through Hertford and Ware:

• North of Priory Street and west of Baldock Street. The western end of the town, where the river and the navigation run close behind the buildings.
• Broadmeads, Amwell End and Station Road. The flat land south of the river around the station, where Pauls Malt ran the town's last working maltings until 1994.
• Between the High Street and the river. The long plots behind the High Street, with the riverside gazebos at their ends.
• Star Street, Cross Street, Plaxton Street and Clements Street. A group of homes and workshops on the low ground near the river.
• Crane Mead Business Park. Commercial buildings on the river side of the town.
• The Pastures Ditch. Properties along this ditch, which joins the Lea just south of Priory Street, flood from it as well as from the river.
• Great Amwell. South of the town, homes in Yearlings Close, Furlong Way and Bridle Way are in Flood Zone 2.

Up the hill, Kingshill, Musley Hill and the fields beyond are in Flood Zone 1. The Environment Agency covers the town with its River Lee at Hertford and Ware warning area, which takes in Stanstead Abbotts as well, and with the River Lee at Hertford alert area, which runs from Lemsford and Hatfield down through Ware. Our live river levels map shows the gauges along the valley and any warning in force.

Search a Ware postcode, from Kingshill to Amwell End

Enter a postcode in the map below to screen an address in Ware against Environment Agency data for rivers, surface water and reservoirs, or use our full flood risk map for anywhere in England. The coral line is the ONS built-up area for Ware, so the town centre, Broadmeads and the estates on the hill fall inside it, while Ware Lock, Wodson Park, Great Amwell and Wareside lie just beyond it.

Embankments, sluices and gauges on the Lea around Ware

The Lea through Ware has been engineered for decades. After the 1947 flood, when the river broke its banks in the town, the Thames Water Authority dredged the channel in 1974, shored up the banks with brick and metal walls and built by-pass sluices at Ware and Hardmead locks, according to the Our Hertford and Ware local history archive. The structures that shape flood risk in the town now are these:

The 2016 study reports that the Environment Agency's Lower Lee strategy of 2013 counted about 31 properties in Ware, Great Amwell and St Margarets at risk in a flood with a 1% chance in any year, and that the strategy depends on the Hardmead and Stanstead sluices continuing to work. The 2026 SFRA says a failure at either sluice would have raised flood risk and lost control of upstream water levels. An assessment beside the river therefore looks at what happens if a gate or a privately kept bank fails, as well as at the zone the site sits in; our explainer on weirs and sluices covers how they hold levels.

The Environment Agency's river gauges near Ware are on the tributaries. The River Ash at Mardock, near Wareside, reached 1.61 m on 22 October 2001, above the 1.30 m at which it expects property flooding, and the River Rib at Wadesmill peaked at 1.99 m the same day. Wareside has its own River Ash warning area, shared with the Hadhams and Widford, and the Agency keeps a rain gauge at Broadmeads in the town.

Ware floods on record, 1947 to 2021

Ware's flood record is mostly local: one serious river flood, in 1947, then surface water on the roads and the odd groundwater incident, logged by the district and county councils since the 1990s.

1. 1947. The Lea broke its banks and caused serious flooding in Ware; the 1974 dredging and sluice works followed.
2. 1993. Ware is among the places in the 18 surface water incidents the district's flood database logged that year.
3. 1999. One of the 13 groundwater flooding incidents in the district's database is recorded in Ware; another follows at Wareside in 2010.
4. 22 October 2001. The Ash at Mardock and the Rib at Wadesmill set the highest levels either gauge has recorded.
5. 13 October 2014. After about nine hours of steady rain on saturated ground, runoff from the playing fields and Walton Road ran down to London Road at Hoe Lane, where one commercial building and three homes flooded inside and out. The county's Section 19 investigation found the road drains overwhelmed, no public sewer serving the 24.6 ha catchment, and residents who remembered earlier floods there.
6. 2015. Ware appears in the district's surface water records again.
7. 25 July 2021. Downstream at Stanstead Abbotts, intense rain and a part-blocked culvert flooded one home inside and three outside on Cappell Lane, which had also flooded in July 2014 and flooded again in May 2024.

The county's own log of internal and external flooding since 1996, summarised in the 2026 SFRA, names Ware, Hertford and Bishop's Stortford as the parts of East Hertfordshire with the most incidents. That record is the reason surface water gets as much attention as the river in a Ware assessment; our guide to surface water flooding and planning explains what the council expects.

Chalk under the town: groundwater and soakaways in Ware

Ware stands on Chalk, mapped by the British Geological Survey as the Lewes Nodular and Seaford formations, but the deposits above it change across the town, and they decide whether rain can soak away on a plot or has to be stored and released slowly:

The two district flood studies read the groundwater record differently. The 2016 SFRA counted 13 groundwater incidents in the council's database, named Ware and Tewin as the places with the most, and found the district's only areas with more than 75% susceptibility to groundwater flooding in Hertford and Ware. The 2026 SFRA notes that neither the Environment Agency's flood outlines nor the county's log since 1996 gives groundwater as a cause, yet its emergence mapping still shows groundwater at or near the surface beside the Lea at Hertford and Ware. It also rates the groundwater under Ware as medium-high in vulnerability to pollution, which matters when runoff is sent into the ground.

For a site on the valley floor, groundwater belongs in the assessment, especially for a basement, a lowered floor or a soakaway. Most of the district also lies within a groundwater Source Protection Zone, which can rule out some infiltration features. Our guides to groundwater flooding and Source Protection Zones explain both, our ground conditions checker gives a first read on a plot, and the BRE 365 calculator works through infiltration test results.

The New River and the Lee Navigation: Ware's man-made waterways

The New River opened in 1613 to carry water from the Chadwell and Amwell springs near Ware to London. It still starts between Hertford and Ware, where a gauge controls how much it takes from the Lea, and runs south through Great Amwell and St Margarets; Thames Water operates it. The 2016 SFRA rates its flood risk as low because it is regulated, but at St Margarets the channel is perched above the land beside it, and the study recommends that an assessment for a nearby site checks overtopping and, where it is perched, a breach. The 2026 SFRA lists the New River and the Lea at Ware among the notable increases in flood extent once climate change is added.

The Lee Navigation runs through the middle of the town, past Ware Lock and the gazebos at the ends of the High Street plots, built by innkeepers and other owners mostly in the 18th and early 19th centuries; about 25 stood in the 1830s and ten by 1980, and several are now Grade II listed. Barges of 100 tons still reached Ware in the 1930s, serving a town the 1880 Ordnance Survey map shows with 107 malt kilns. The 2026 SFRA asks any development next to a canal to show how a breach would affect the site, and a boundary on the water brings duties of its own, set out in our guide to riparian ownership.

Which policies apply to a planning application in Ware?

East Hertfordshire District Council decides applications in Ware under the East Herts District Plan, adopted on 23 October 2018 and running to 2033. Hertfordshire County Council, as Lead Local Flood Authority, comments on the surface water drainage of major schemes. A Ware application has to answer these:

• Policy WAT1. Flood risk management: the sequential approach, the exception test where it applies, no inappropriate development in the functional floodplain, and no rise in flood risk on the site or downstream.
• Policy WAT5. Sustainable drainage: the SuDS hierarchy, greenfield runoff rates as the aim, and a long-term maintenance plan.
• Policies WARE2 and WARE3. The allocation north and east of the town, which must provide sustainable drainage, flood mitigation and a new foul sewer, and the protected employment areas at Broadmeads, Crane Mead, Marsh Lane, Park Road and Star Street.
• The Ware Neighbourhood Plan. Made on 13 December 2023 after a referendum in which 90.8% voted yes, it runs to 2033 and forms part of the development plan for the town (East Herts Council).
• The 2026 Level 1 SFRA. JBA's study for the next Local Plan, issued in September 2026; scoping on that plan closed in July 2026, and the next consultation is due in February 2027.
• County drainage guidance. Hertfordshire's guidance for developers (updated August 2021): no rise in peak discharge up to the 1 in 100 year storm plus climate change, greenfield rates on greenfield land, no flooding on site in a 1 in 30 year storm, and infiltration tested to BRE 365.

Above these, a Ware application is judged against chapter 18 of the August 2026 NPPF, where policy F4 says when an assessment is needed, F5 and F6 set the sequential and exception tests, and F8 asks every development to meet the 2025 national standards for sustainable drainage. District-wide validation and drainage requirements are on our East Hertfordshire council page, and the county picture is on our Hertfordshire page.

Land north and east of Ware: the allocation on the boulder clay

Most of Ware's planned growth is on the fields north and east of the town. Policy WARE2 allocates the land for at least 1,000 homes by 2033, with 500 more if the county agrees the road mitigation, plus about 3 ha of employment land, schools and a link road between Widbury Hill and the A10. An application, 3/22/2406/FUL, proposes up to 1,800 homes there. The 2016 SFRA tested the land as three parcels:

The land is clear of river flooding, but the study flagged surface water on the two larger parcels and said detailed hydraulic modelling would be needed to confirm the risk. On boulder clay, drainage shapes the layout: storage, open routes for overland flow and a discharge rate the county will accept all need room on the plan. WARE2 also needs a new foul sewer from the north of the town to existing infrastructure, with any pumping stations that requires.

Smaller sites come forward too: conversions of riverside buildings and former maltings, infill on the hill, and extensions in the valley streets. A site in Flood Zone 2 or 3 that is not allocated starts with the sequential test, which asks whether the development could go on land at lower risk.

From the High Street backs to the northern fields: when an assessment is needed

WAT1 and chapter 18 of the NPPF decide when a planning application in Ware needs a flood risk assessment, and the Environment Agency's standing advice covers minor extensions. Applied to the kinds of site that come forward in the town:

Our guides to when a flood risk assessment is needed and to the Environment Agency's standing advice go through the national triggers and the extension rules in more detail.

What we prepare for sites in Ware, from the wharves to the plateau

Work in Ware runs from a single house purchase in Amwell End to drainage for hundreds of homes north of the town. Our consultants are chartered, and a senior consultant checks and signs off every report. Reports for sites in Ware come from Unda Consulting Limited, a CIWEM Business Partner.

• Applications by the river. Homes, conversions and commercial schemes in the Lea's flood zones need a flood risk assessment for planning that answers WAT1.
• Every source in one report. A flood risk assessment in Ware weighs the Lea, the Pastures Ditch, runoff from the slopes, groundwater in the valley gravels and the privately kept banks that protect the town.
• Before exchange. Buyers on the valley streets, in Great Amwell or in Stanstead Abbotts can commission a flood risk survey for property purchase that looks at the house itself and the way water would reach it.
• New homes in Flood Zone 3. Dwellings on the low ground by the navigation need a sequential and exception test showing why land at lower risk cannot take them and how they will stay safe.
• Drainage for major schemes. The county, as Lead Local Flood Authority, expects a drainage strategy for major applications showing that runoff will not exceed today's rate.
• Gravel or clay. A surface water drainage strategy tests the Kesgrave gravels for soakaways and falls back to storage and a controlled outfall on the boulder clay north of the town.
• After permission. Where a Ware permission has a drainage condition attached, discharge of drainage conditions supplies the details and the maintenance plan the council asks for.
• Water in the Chalk and gravels. Both district studies place groundwater near the surface on the valley floor in Ware, so a groundwater flood risk assessment belongs in the brief before a basement or a soakaway goes into a scheme there.
• Levels for the northern land and the New River. Detailed flood modelling meets the SFRA's call for hydraulic modelling on the WARE2 parcels and for breach checks beside the New River.
• When the Lea rises. Sites in the River Lee at Hertford and Ware warning area may need a flood warning and evacuation plan setting out how occupants leave or stay safe.
• Premiums on the valley streets. Householders in the flood zone, or near London Road where homes flooded in 2014, use a flood risk assessment for insurance when cover is refused or the premium jumps.
• Employment land. New buildings in the Broadmeads, Crane Mead or Park Road employment areas, or on the 3 ha planned north of the town, can use a BREEAM flood risk assessment for the flood credit.
• Businesses beside the river. Crane Mead Business Park sits in the flood zone, and a business continuity flood risk assessment sets out what a flood would mean for a firm's premises and work.
• Wastewater from new homes. WARE2 depends on a new foul sewer from the north of Ware, and a foul drainage strategy shows where a scheme's wastewater goes and whether the network can take it.

Reporting a flood in Ware, Wareside or Stanstead Abbotts

If floodwater puts anyone in danger, call 999; for a power cut, ring 105. For everything else in and around Ware, each organisation below covers part of the town's flood risk:

Upstream, our Hertford page covers the town where the Beane, the Mimram and the Rib meet the Lea, and the whole river from Luton to Bow Creek is on our River Lea page. South-east of Stanstead Abbotts the Stort forms the county boundary, and Essex has a page of its own.

Ware flood risk: what applicants and buyers ask

Unda Consulting Limited prepares flood risk assessments, sequential and exception tests and drainage strategies for sites across Ware, Great Amwell, Stanstead Abbotts and Wareside. To talk one through, call 01293 214444 or email enquiries@unda.co.uk.