Photo: Bill Boaden · CC BY-SA 2.0Heavy rain is Lincoln’s main flood risk: 9.1% of homes, against 6% from rivers or the sea
On the Environment Agency’s maps, which allow for flood defences, “high or medium” means at least a 1 in 100 chance of flooding from rivers or the sea in any year. For hazard risk, Lincoln grades D: #48 of 61 in Lincolnshire.
What stands out about Lincoln’s hazards
From the Environment Agency’s maps and records and the BGS radon atlas, below.
What Lincoln faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Rivers and the sea
Surface water
Past floods
The River Witham
Flood warnings
Radon
Lincoln grades D for hazard risk
Flood risk from rivers and the sea, against all UK towns.
The share of homes at high or medium risk from rivers and the sea, ranked against every UK town of 1,000 or more: fewer homes at risk is better. Towns with none at high or medium risk are ordered by their share at low risk, so they don’t all share one score. Surface water and radon aren’t graded: they are described below.
Where the water goes in Lincoln
Turn layers on and off. Blue is the risk from rivers and the sea; pink is where heavy rain collects. Both allow for flood defences.
The river and sea risk follows the River Witham, the Sincil Dyke and the Great Gowts Drain. Surface-water risk is spread across the city, in dips, underpasses and along small streams, which is why more homes are exposed to it.
6% of Lincoln’s homes are at high or medium risk from rivers or the sea
The Environment Agency’s national map, allowing for defences. A further 9.2% are at low risk.
Share of each UK town’s homes at high or medium risk from rivers and the sea. 35% of UK towns have none; Lincoln has more than 92% of towns.
| # | Town | People | High or med. | |
|---|---|---|---|---|
| 1 | Oldham Greater Manchester | 110,722 | 0% | |
| 2 | Birkenhead Merseyside | 109,854 | 0% | |
| 3 | Kensington and Chelsea London | 143,348 | under 0.1% | |
| … | ||||
| 71 | Preston Lancashire | 94,502 | 4.7% | |
| 72 | Bath Somerset | 94,080 | 5.6% | |
| 73 | Lincoln Lincolnshire | 104,553 | 6% | |
| 74 | Grimsby Lincolnshire | 85,915 | 8.9% | |
UK towns of 73,000 to 146,000 people.
The Environment Agency’s Risk of Flooding from Rivers and Sea (NaFRA2, June 2026) counts each postcode’s homes by band; the shares weight those postcodes by Census 2021 households. The EA counts include homes built since 2021.
Heavy rain puts about 1.5 times as many Lincoln homes at risk as rivers and the sea do
Surface water is rain that falls faster than drains and the ground can take it. It is mapped separately from rivers and the sea, and it is not in the Hazard risk Grade.
About 4.6% of homes are at high risk of surface-water flooding (a 1 in 30 chance or more each year) and 4.6% at medium risk: roughly 3,950 households. A further 9.4% face a low risk from surface water. That is more than 90% of UK towns.
Our estimate: every address in the city (ONS NSUL) read on the Environment Agency’s Risk of Flooding from Surface Water map (NaFRA2, 2025), each postcode’s share weighted by its Census 2021 households. Neither agency publishes a count of homes for surface water, so treat it as a guide; one street can differ from the next.
Lincoln has flooded in 7 recorded years since 1795, most of all in 1947
Every flood the Environment Agency has mapped inside Lincoln’s built-up area, newest first. The record is fullest for big river floods; small and surface-water floods are often missing.
- 2025January 2025: River flooding recordedUnder 1 hectare inside today’s built-up area
- 2024January 2024: The River Witham overflowed5 hectares inside today’s built-up area
- 2023October 2023: The River Witham overflowed4 hectares inside today’s built-up area
- 2019November 2019: River flooding recorded1 hectare inside today’s built-up area
- 1981April 1981: River flooding recorded1 hectare inside today’s built-up area
- 1947March 1947: River flooding recorded245 hectares inside today’s built-up area
Show all 7
- 1795February 1795: The sea came in156 hectares inside today’s built-up area
Floodwater covered 245 hectares of what is now Lincoln in 1947, the largest flood the record holds here (March).
4,793 of Lincoln’s households today live inside the outline of a recorded flood.
Since 1947, the largest recorded flood inside the city covered 5 hectares.
The River Witham at Bargate Weir: highest 1.38 m, in October 2023
The highest level each winter (October to September) at the Environment Agency’s Bargate Weir gauge (Boultham), since 2011. The river normally runs between 0.00 m and 0.59 m here.
- 19 February 201329.22 m
- 16 January 20168.20 m
- 27 July 20146.51 m
- 8 June 20146.50 m
- 2 July 20146.50 m
- 16 July 20146.50 m
The River Witham has topped its normal range on 5,033 days since 2011, most in the winters of 2019–20 and 2013–14. By its highest day, the winter of 2025–26 was the 12th-highest of the 14.
Environment Agency Hydrology API, Bargate Weir (station E2900), daily maximum level; the record and normal range from the EA’s stage scale. Live river levels are on GOV.UK’s Check for flooding.
No flood warning or alert is in force for Lincoln · 4 warnings in 20 years
The Environment Agency has 5 flood warning areas and 4 alert areas reaching into the city; warnings since the service began in 2006.
Of the 4 warnings, 2 were for Watercourses in the Lincoln area and 1 for River Witham and South Delph from Lincoln to Washingborough. 2007 had the most warnings (2); 2019 the most alerts (24).
The most recent warning was on 1 March 2026.
Show the 9 warning and alert areas
| Area | Kind | Since 2006 | Now |
|---|---|---|---|
| Watercourses in the Lincoln area | Warning area | 2 | None |
| River Witham to the east of Lincoln | Warning area | 1 | None |
| River Witham and South Delph from Lincoln to Washingborough | Warning area | 1 | None |
| Fossdyke Canal and Tributaries from Torksey to Lincoln including Saxilby | Warning area | 0 | None |
| Isolated properties and villages near the River Witham and River Brant from Claypole to Lincoln | Warning area | 0 | None |
| Witham in North Kesteven | Alert area | 64 | None |
| Lincoln Watercourses | Alert area | 41 | None |
| Lower River Witham | Alert area | 37 | None |
| Fossdyke Canal | Alert area | 34 | None |
Environment Agency Historic Flood Warnings (first issues only, not updates; “flood watch” counted as an alert before 2011) and the real-time flood-monitoring API. Sign up for free warnings on GOV.UK or call Floodline, 0345 988 1188.
Parts of Lincoln are in radon Affected Areas, up to the Over 30% band
Radon is a natural radioactive gas from the ground; long exposure raises the risk of lung cancer. The atlas gives the chance that a home in each 1 km square is above the UK action level (200 Bq/m³).
67% of Lincoln’s built-up area is in a radon Affected Area (1% of homes or more above the action level), and 32% in squares of 5% or more, mostly on the east side of the city.
The squares are indicative: each takes the highest band found anywhere inside it, so most homes in a coloured square are below it. Only a three-month test in the home gives a real answer.
BGS/UKHSA Indicative Atlas of Radon in Great Britain, version 3. Check an address at UKradon.org.
Flood risk in the places around Lincoln
Share of homes at high or medium and at low risk from rivers and the sea. Tap a town for its page.
| Town | People | High or medium | Low | Hazard |
|---|---|---|---|---|
| Lincoln | 104,553 | 6% | 9.2% | D |
| Bracebridge Heath | 5,794 | 0% | 0% | A |
| Skellingthorpe | 3,116 | 5% | 6.6% | D |
| North Hykeham | 16,855 | 0.8% | 0.8% | C+ |
| Waddington | 6,828 | 0% | 0% | A |
| Washingborough and Heighington | 6,386 | 3.1% | 1.2% | C− |
| Nettleham | 3,418 | 2.6% | 3.6% | C− |
| Branston | 4,285 | 0.3% | under 0.1% | B− |
Lincoln has more homes at high or medium risk than any neighbour in the table. Bracebridge Heath and Waddington have none.
Get ready for what Lincoln faces
Free warnings, what to do in a cloudburst, and what to check before you move.
- Sign up free for Environment Agency flood warnings by text, call or email.
- Floodline: 0345 988 1188, 24 hours.
- Lincoln’s warning areas include Watercourses in the Lincoln area and River Witham and South Delph from Lincoln to Washingborough.
- Surface water rises in minutes, often with no warning issued: stay out of underpasses and dips.
- Keep the gullies and drains outside your home clear of leaves.
- Report a blocked road drain to the council.
- Test over three months, in a living room and a bedroom.
- Above 200 Bq/m³, a small sump and fan usually fixes it.
- New homes in radon areas are built with protection: basic from 3%, full from 10%.
- Check the address on GOV.UK’s long-term flood risk service: it gives rivers and sea and surface water separately.
- Ask whether the home has flooded or had a flood insurance claim; the TA6 property form asks the seller.
- Homes built before 2009 can get flood cover through Flood Re, the government-backed scheme; newer homes can’t.
- Check radon for the address on UKradon.org (a small fee) or ask the seller for a test result.
What this data can and can’t tell you
- Defences are counted. Both agencies’ maps allow for flood defences and the chance they are overtopped or fail, so a town behind a defence scheme can show few homes at high risk and many at low risk.
- Surface water is our estimate. Neither agency publishes a count of homes at risk from surface water, so we read each address on the map. A flat on a hill and a basement in a dip can share a postcode.
- Past floods are what was recorded. The flood outlines come from surveys, aerial photographs and reports; many small floods, and most surface-water floods, were never mapped.
- One town, many streets. Risk is street by street. Check a specific address on GOV.UK’s long-term flood risk service before you buy or rent.
Questions about flooding and hazards in Lincoln
Does Lincoln flood?
The last flood the Environment Agency recorded inside the city was in January 2025. 6% of homes are at high or medium risk from rivers and the sea on the Environment Agency’s maps, which allow for flood defences. About 9.1% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Lincoln grades D for hazard risk against UK towns.
Which parts of Lincoln are at risk of flooding?
From rivers and the sea, the places the Environment Agency warns directly: Watercourses in the Lincoln area, River Witham and South Delph from Lincoln to Washingborough, River Witham to the east of Lincoln and Isolated properties and villages near the River Witham and River Brant from Claypole to Lincoln. Surface water can collect in low spots anywhere in the city. Check a specific address on GOV.UK’s long-term flood risk service.
When did Lincoln last flood?
The recorded flood outlines inside the city run from 1795 to 2025 (7 years); the largest was in 1947. Flood warnings have been issued for parts of the city since 2006, most recently on 1 March 2026.
Is Lincoln at risk of surface water flooding?
About 4.6% of homes are at high risk and 4.6% at medium risk from surface water, against 6% at high or medium risk from rivers and the sea. Surface water floods come with little warning, and the agencies don’t issue warnings for them.
Is radon a problem in Lincoln?
67% of the city’s built-up area is in a radon Affected Area on the BGS/UKHSA atlas, and 32% is in 1 km squares where 5% or more of homes may be above the action level. Most homes are below it; a three-month test is the only way to know.
Are there flood warnings in Lincoln now?
No flood warning or alert was in force near Lincoln at 15 November 2026, 08:27. Live warnings are on GOV.UK’s Check for flooding service and Floodline, 0345 988 1188.
Contains Environment Agency information © Environment Agency and/or database right 2026. Contains British Geological Survey materials © UKRI 2026.
Sources: Environment Agency Risk of Flooding from Rivers and Sea, postcodes in areas at risk (June 2026); Natural Resources Wales Flood Risk Assessment Wales (May 2026); ONS Census 2021 households by postcode · Environment Agency Risk of Flooding from Surface Water (NaFRA2, 2025) and Natural Resources Wales Flood Risk Assessment Wales surface water and small watercourses, read at every address (ONS National Statistics UPRN Lookup, September 2026) and weighted by Census 2021 households by postcode · Environment Agency Recorded Flood Outlines and Natural Resources Wales historic flood map, inside the ONS 2022 built-up-area boundary · Environment Agency Hydrology API (daily maximum river level) and flood-monitoring stage scales · Environment Agency real-time flood-monitoring API · Environment Agency Historic Flood Warnings (January 2006 to June 2026) and flood warning and alert areas · BGS/UKHSA Indicative Atlas of Radon in Great Britain, version 3, by 1 km square · TownRatings grades: our own summary of the data, ranked against UK towns only. All under the Open Government Licence v3.0.
Contains public sector information licensed under the Open Government Licence v3.0. Contains HM Land Registry data © Crown copyright and database right 2026. Contains OS data © Crown copyright and database right 2026 (ONS boundaries). Northern Ireland: Source: NISRA; contains Land & Property Services data and Ordnance Survey of Northern Ireland information, © Crown copyright, licensed under the Open Government Licence v3.0. Scotland: contains National Records of Scotland data, Registers of Scotland data and SEPA data, © Crown copyright / © SEPA 2025, licensed under the Open Government Licence v3.0.