Flood Risk Assessment in Witney

A flood risk assessment in Witney, Oxfordshire, starts with the River Windrush and the narrow gap it has to squeeze through at Bridge Street. Four smaller channels join it in or just below the town: the Hailey Road Drain, Madley Brook, Colwell Brook and Emma's Dyke. In 2007, 2020 and 2024 the river and those brooks between them put water into homes and shops around the centre. We write flood risk assessments in Witney for planning applications, house purchases, mortgage lenders and insurers, and prepare sequential and exception tests and surface water drainage strategies alongside them.

On this page Witney means the built-up area drawn by the Office for National Statistics, all of it in the OX28 postcode district. That takes in the town centre and West End, Woodgreen and Newland north of the river, Cogges and Madley Park to the east, and the estates running south towards the A40, Burwell Meadow and Thorney Leys among them. West Oxfordshire District Council decides planning applications, and Oxfordshire County Council is the lead local flood authority. Ducklington, Curbridge, Hailey and Minster Lovell lie outside the outline, in OX29.

The Windrush at Riverside Gardens peaked at 2.45 m just after midnight on Christmas Day 2020, the highest reading on the gauge. At least 54 homes and businesses flooded inside, and residents of Mill House Care Home had to be evacuated.

To ask about a Witney address, call 01293 214444 or email enquiries@unda.co.uk. Before we quote, we check the flood zone, the warning area and the investigation reports for that street.

Where does Witney flood? The Windrush and the brooks that meet it in town

Along a valley-floor strip through the centre, plus the lower reaches of the brooks. The Windrush runs north to south through Witney in a straightened channel, then splits into several channels among the gravel pits below the town before joining the Thames about 8.5 km downstream. The council's 2025 flood study puts the buildings in Flood Zone 3 mostly along or beside Bridge Street, with others on Church Lane from Madley Brook and on Eastfield Road from the Hailey Road Drain.

The Environment Agency's River Windrush at Witney and Ducklington warning area covers the town down to Hardwick, and its gauge at Riverside Gardens normally reads between 0.46 m and 1.40 m. Our live river levels map shows that gauge and any warning in force as the river rises.

Search an OX28 address on the map

Type a Witney postcode below to see the planning flood zones, surface water extents and any live warning, or open the full flood risk map. Our own overlay of the Environment Agency's Flood Map for Planning on this outline puts about 10% of the built-up area in Flood Zone 2 or 3 and about 4% in Flood Zone 3.

Bridge Street, and the floods of 2007, 2020 and 2024

Every Witney investigation comes back to the same place. Bridge Street and the buildings just below it hold back flood flows, so once the open floodplain upstream is full the water has nowhere to go but into the streets around the bridge.

1. 20 and 21 July 2007. 84 mm fell on the town in 17 hours on the Friday, flooding the Hailey Road Drain, Madley Park and Burwell Meadow. On the Saturday the river arrived from the Cotswolds, the Worsham gauge peaked at 29.26 m3/s against a previous record of 18.90, and water reached the underside of the town bridge. Witnesses described a rise of up to a metre in half an hour; fire crews broke in Bridge Street front doors to free trapped residents. About 240 properties flooded (Environment Agency review, February 2008).
2. December 2013 to February 2014. Long, steady rain kept the river high for weeks. Homes and businesses in West End, Bridge Street and Riverside Gardens flooded inside, and Hailey Road and Eastfield Road flooded on 23 and 24 December.
3. 23 to 25 December 2020. Heavy rain first overwhelmed road drains whose outfalls were already blocked by the high river, then the catchment flow arrived and Worsham peaked at 30.348 m3/s, above 2007. At least 54 homes and businesses flooded inside, in Woodford Mill, Riverside Gardens, Bridge Street, West End, Millers Mews, Newland and Eastfield Road. The warning came after properties had flooded, and the event exceeded the modelled 1 in 100 year flood (district investigation, January 2022).
4. 25 and 26 November 2024. Storm Bert put 68.69 mm on the catchment over two days. The warning was issued at 11:15 on 25 November and the gauge peaked at 2.31 m that evening. The district council confirmed 15 homes and businesses flooded inside, along Riverside Gardens, Bridge Street and Millers Mews and on the West End Industrial Estate, where five units flooded even though gates and pumps had been fitted after 2020 (county investigation, published January 2026).

After 2020 the Environment Agency revised the level at which it considers a warning, so that one gives two hours' notice of property flooding, and added an alarm on the Worsham flow. In March 2025 it told Witney Town Council that it is rebuilding its Windrush model through the town, including the Hailey Road Drain, with an economic assessment of a possible scheme to follow. Our note on Section 19 reports explains how these investigations are triggered and what their findings mean for a site.

Welch Way, Thorney Leys and the streets the newer flood studies flag

The council commissioned new flood studies for its Local Plan 2043: a Level 1 assessment in 2025 and a Level 2 assessment of candidate sites in April 2026, both still marked draft. They show where Witney's risk grows under climate change and where rain on the town itself does the damage.

• A new river extent under climate change. With the central climate allowance for the 1% flood, the river spreads along Welch Way, High Street, Queen Emma's Dyke and Gordon Way, joining up with Emma's Dyke and reaching Witney Community Hospital. Further properties on Bridge Street and Witan Way and the westernmost homes in Cogges fall inside the larger extent.
• Today's Flood Zone 2. Mill Street, High Street, Welch Way and Cogges Hill Road all have properties in Flood Zone 2.
• Surface water on the roads. High risk of surface water flooding along Welch Way, Moorland Road, High Street, Woodford Way, Queen Emma's Dyke, Thorney Leys, Hailey Road and Eastfield Road, with incidents recorded off Woodford Way and Eastfield Road in 2020.
• Sewer flooding. Thames Water's records give the OX28 district 19 sewer flooding incidents, five of them inside buildings. In November 2024 the surface water sewer under Bridge Street took in foul water and surcharged onto the road.
• Groundwater. Shallow lime-rich soils over parts of Witney drain freely and allow a mobile water table, which the 2025 study rates as moderate groundwater risk.

Both studies are on the council's Local Plan 2043 evidence page. The Level 2 assessment also says its river models predate the latest climate allowances, which is why a site near any of these streets usually needs more than a flood zone check.

What West Oxfordshire asks of a flood risk assessment in Witney

Policy EH7 of the West Oxfordshire Local Plan 2031, adopted on 27 September 2018, decides when a Witney application needs an assessment and what it must cover. The draft Local Plan 2043 finished its pre-submission consultation on 9 October 2026 and has not yet been examined, so EH7 still governs.

Oxfordshire County Council comments on drainage for major schemes only; smaller proposals are judged by the district against EH7. Our West Oxfordshire council page sets out the council's validation and policy requirements in more detail, and minor extensions in Flood Zone 2 or 3 can often follow the Environment Agency's standing advice in place of a full report.

North Witney, Welch Way and the growth planned south and west

Most of Witney's coming housing sits on the edge of the town, where the brooks rise, so the drainage of each site decides how much more water reaches the streets that already flood.

• North Witney (WIT2, 2031 plan). An outline application for about 1,250 homes was submitted in February 2024, and revised documents answering concerns about flood risk and transport were out for consultation when the draft 2043 plan was written. The council's 2015 study said a site assessment must show the Hailey Road Drain culvert is not exceeded in a 1 in 30 year storm and set floor levels at least 300 mm above the 1 in 100 year level with climate change.
• Welch Way (draft WIT4). The April 2026 study assessed a 5 ha town-centre site here for 50 to 100 homes. Most of it lies inside the Witney warning area, in an abandoned river meander crossed by two small watercourses.
• Land south of Witney (draft WIT5). About 700 homes on 108 ha south of the A40 beside the sewage works. Colwell Brook runs across the site, and the land falls towards it.
• West of Witney and north of Burford Road (draft WIT6, WIT7). About 700 homes in each location. On the land the April 2026 study assessed west of the town, south of Downs Road, headwater drains of Colwell Brook run through the south-east corner, with the Windrush about 275 m to the north.

Where a ditch or culvert runs along a plot boundary, its upkeep usually falls to the landowner, as the 2020 investigation reminded Witney's riverside owners. Our notes on riparian ownership and on culverts cover who keeps a channel clear and when works in it need consent.

Draining a Witney site: soakage, culverts and Thames Water

The county wants water put back into the ground first, and the lime-rich soils over parts of Witney often allow it. Where they do not, the next outlet is a brook, and in Witney most of the brooks are main rivers running through culverts with little spare room.

• Test the ground first. Three BRE 365 tests at the depth of the proposed soakaway, with the lowest rate used; our BRE 365 infiltration rate calculator turns the readings into a rate. Winter monitoring may be needed to show the water table sits a metre below the base.
• A brook or the river next. An outfall to the Windrush or to a main river reach of the Hailey Road Drain, Madley Brook or Colwell Brook is a matter for the Environment Agency as well as the county, which judges the rate. Upstream ordinary watercourses are consented by the district on the county's behalf.
• Sewers last. Thames Water must agree any surface water connection, and the 2015 study recorded that sewer upgrades were likely to be needed in Witney as the town grows.
• Basements near the river. Many Bridge Street buildings have basements, and river water entered at least two in November 2024; a new basement or cellar conversion in the warning area needs its own flood case.

Which body regulates a channel decides who grants consent: the Environment Agency on the main rivers, the council elsewhere. Our guide to main rivers and ordinary watercourses sets out the difference, and the 2025 national standards for sustainable drainage explain the order of outlets a scheme is expected to follow.

Reports for Witney sites, from Madley Park to Thorney Leys

Which report a Witney site needs depends on who is asking for it: the district council, the county, a lender, an insurer or Thames Water.

• Applying to West Oxfordshire. Any Witney proposal in Flood Zone 2 or 3, on a hectare or more, or in a critical drainage area needs a flood risk assessment for planning answering Policy EH7 and the council's 2025 and 2026 flood studies.
• All the sources on one plot. A flood risk assessment for a Witney site weighs the Windrush, the brook or drain nearest the plot, runoff down roads such as Hailey Road, the limestone water table and Thames Water's sewers, then sets floor levels and a dry route out.
• Buying near Bridge Street or Millers Mews. Where a search flags the Windrush warning area or a street that flooded in 2020 or 2024, a flood risk survey for property purchase looks at the building itself: its thresholds, the way water reached it and what a lender will ask.
• Homes on the valley floor. New dwellings in Flood Zone 2 or 3 on a plot the Local Plan has not allocated need a sequential and exception test report showing why no lower-risk site across the search area could take them, which EH7 applies before anything else.
• Any new roof or yard. EH7 and draft Policy CP5 both expect sustainable drainage with its upkeep secured, and a drainage strategy sets out the route, the rates and the storage for the site.
• Fields at North Witney, plots off Burford Road. A greenfield edge must shed no more water once built on, and north of the town that water reaches the Hailey Road Drain culvert; a surface water drainage strategy fixes the discharge rate Oxfordshire County Council will accept and sizes storage for it.
• Once permission is granted. Where a West Oxfordshire decision notice includes a drainage condition, we prepare the calculations, maintenance plan and drawings for the discharge of drainage conditions.
• Homes and firms flooded twice. Bridge Street and Riverside Gardens took water in 2020 and again in 2024, and businesses at Bridge Street Mills told the 2020 investigation they could no longer get cover; a flood risk assessment for insurance sets out for an underwriter what the building now faces.
• Tributaries the national model leaves out. The Environment Agency's 2014 Windrush model does not include the brooks through the town and is being rebuilt; for a plot beside the Hailey Road Drain, Madley Brook or Colwell Brook, flood modelling sets the levels a scheme has to meet.
• Units on the West End Industrial Estate. Five units flooded there in November 2024 after the gates and pumps fitted since 2020 failed, and a business continuity flood risk assessment helps an occupier plan for the next rise of the ditches behind it.
• Care homes and flats by the river. Mill House Care Home and Riverside House were evacuated in December 2020 after a warning that came too late, so a flood warning and evacuation plan for a site in the Witney warning area spells out who leaves, when and by which route.

Ducklington, Hailey, Curbridge and Minster Lovell

Ducklington sits just south of the outline, where Colwell Brook and Emma's Dyke reach the Windrush and the Witney warning area runs on to Hardwick. Hailey lies on the high ground the Hailey Road Drain comes from, Curbridge is to the south-west beyond the land west of the town, and Minster Lovell is upstream on the Windrush. We prepare flood risk assessments for sites in each of them against the same West Oxfordshire policies.

For the rest of the county see our Oxfordshire page. Oxford, Abingdon, Banbury and Bicester have pages of their own, and the River Thames page follows the river the Windrush feeds. Every place we cover is listed on our areas index.

Who handles flood water in Witney, and how to reach them

If anyone is in danger, call 999. Once everyone is safe, who to contact depends on where the water came from:

For a quick reading on one Witney address before calling anyone, GOV.UK's long-term flood risk service gives its river, surface water and reservoir ratings.

Questions Witney owners, buyers and applicants ask us

For anything else about a site in Witney, call one of our experienced flood risk consultants on 01293 214444 or email enquiries@unda.co.uk. Reports for sites in Witney come from Unda Consulting Limited, a CIWEM Business Partner.