Photo: My another account · CC BY-SA 3.0Surface water, more than the river, is Melksham’s flood risk: 5.6% of homes, against 0.7% 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, Melksham grades C+: #20 of 30 in Wiltshire.
What stands out about Melksham’s hazards
From the Environment Agency’s maps and records and the BGS radon atlas, below.
What Melksham 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 Clackers Brook
Flood warnings
Radon
Melksham grades C+ 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 Melksham
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 Bristol River Avon. Surface-water risk is spread across the town, in dips, underpasses and along small streams, which is why more homes are exposed to it.
0.7% of Melksham’s homes are at high or medium risk from rivers or the sea
The Environment Agency’s national map, allowing for defences. A further 3.6% 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; Melksham has more than 62% of towns.
| # | Town | People | High or med. | |
|---|---|---|---|---|
| 1 | Little Hulton Greater Manchester | 25,824 | 0% | |
| 2 | Coseley West Midlands | 25,206 | 0% | |
| 3 | Wickersley and Bramley South Yorkshire | 24,653 | 0% | |
| … | ||||
| 184 | Gorseinon West Glamorgan | 14,114 | 0.6% | |
| 185 | Heckmondwike West Yorkshire | 13,368 | 0.6% | |
| 186 | Melksham Wiltshire | 18,277 | 0.7% | |
| 187 | Bourne Lincolnshire | 17,495 | 0.7% | |
| 188 | Wath upon Dearne South Yorkshire | 16,962 | 0.7% | |
| … | ||||
| 335 | Dunscroft and Hatfield South Yorkshire | 14,000 | 51% | |
| 336 | Goole East Riding of Yorkshire | 20,173 | 94% | |
UK towns of 13,000 to 26,000 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 8.6 times as many Melksham 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 3% of homes are at high risk of surface-water flooding (a 1 in 30 chance or more each year) and 2.6% at medium risk: roughly 450 households. A further 7.9% face a low risk from surface water. That is more than 74% of UK towns.
Our estimate: every address in the town (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.
Melksham has flooded in 18 recorded years since 1900, most of all in 1932
Every flood the Environment Agency has mapped inside Melksham’s built-up area, newest first. The record is fullest for big river floods; small and surface-water floods are often missing.
- 2014January 2014: River flooding recordedUnder 1 hectare inside today’s built-up area · This represents flooding in the area in
- 2013December 2013: River flooding recordedUnder 1 hectare inside today’s built-up area · This represents flooding in the area in and
- 2012April and November 2012: River flooding recorded2 hectares inside today’s built-up area · This represents flooding in the area in
- 2009February 2009: River flooding recorded3 hectares inside today’s built-up area · North Wessex
- 2000October 2000: River flooding recordedUnder 1 hectare inside today’s built-up area · This represents flooding in the area in
- 1999January 1999: River flooding recorded1 hectare inside today’s built-up area
Show all 18
- 1992December 1992: River flooding recorded1 hectare inside today’s built-up area
- 1982March 1982: The River Avon overflowed5 hectares inside today’s built-up area
- 1979January and December 1979: River flooding recorded9 hectares inside today’s built-up area
- 1978March 1978: River flooding recorded1 hectare inside today’s built-up area · This represents flooding in the area in
- 1974September 1974: River flooding recordedUnder 1 hectare inside today’s built-up area
- 1971June 1971: River flooding recordedUnder 1 hectare inside today’s built-up area · This represents flooding in the area in
- 1968July 1968: River flooding recorded14 hectares inside today’s built-up area · This represents flooding in the area in
- 1963November 1963: River flooding recordedUnder 1 hectare inside today’s built-up area · This represents flooding in the area in
- 1960December 1960: River flooding recorded14 hectares inside today’s built-up area
- 1932May 1932: River flooding recorded32 hectares inside today’s built-up area
- 1925January 1925: River flooding recorded27 hectares inside today’s built-up area
- 1900January 1900: River flooding recordedUnder 1 hectare inside today’s built-up area · This represents flooding in the area
Floodwater covered 32 hectares of what is now Melksham in 1932, the largest flood the record holds here (May).
199 of Melksham’s households today live inside the outline of a recorded flood.
Since 1932, the largest recorded flood inside the town covered 14 hectares.
The Clackers Brook in November 2024 rose to its 4th-highest level since 2017
The highest level each winter (October to September) at the Environment Agency’s Melksham Clackers gauge, since 2017. The river normally runs between 0.00 m and 0.60 m here.
- 28 October 20175.15 m
- 6 November 20175.15 m
- 23 September 20241.47 m
- 24 November 20241.43 m
- 4 January 20241.41 m
- 21 January 20181.27 m
The Clackers Brook has topped its normal range on 165 days since 2017, most in the winters of 2023–24 and 2025–26. By its highest day, the winter of 2025–26 was the 4th-highest of the 9.
Environment Agency Hydrology API, Melksham Clackers (station 531188), 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 Melksham · 1 warning in 20 years
The Environment Agency has 1 flood warning area and 2 alert areas reaching into the town; warnings since the service began in 2006.
Of the 1 warnings, 1 were for Bristol Avon (mid) at Melksham. 2024 had the most warnings (1); 2012 the most alerts (41).
The most recent warning was on 24 November 2024.
Show the 3 warning and alert areas
| Area | Kind | Since 2006 | Now |
|---|---|---|---|
| Bristol Avon (mid) at Melksham | Warning area | 1 | None |
| Mid Bristol Avon area | Alert area | 193 | None |
| Upper Bristol Avon area | Alert area | 184 | 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.
Melksham is in the lowest radon 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).
Every 1 km square over Melksham is in the lowest band: fewer than 1 in 100 homes are expected to be above the action level.
BGS/UKHSA Indicative Atlas of Radon in Great Britain, version 3. Check an address at UKradon.org.
Flood risk in the places around Melksham
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 |
|---|---|---|---|---|
| Melksham | 18,277 | 0.7% | 3.6% | C+ |
| Berryfield | 1,094 | 0% | 0% | A |
| Bowerhill | 3,976 | 0% | 0% | A |
| Holt | 1,704 | 0% | 1.2% | B+ |
| Atworth | 1,293 | 0% | 0% | A |
| Bromham | 1,066 | 0% | 0% | A |
| Corsham | 10,887 | 0.5% | 0.2% | C+ |
| Trowbridge | 43,753 | 0.2% | 0.9% | B− |
Melksham has more homes at high or medium risk than any neighbour in the table.
Get ready for what Melksham 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.
- Melksham’s warning areas include Bristol Avon (mid) at Melksham.
- 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.
- Never walk or drive through floodwater: 30 cm of moving water can float a car.
- Move valuables, papers and medicines upstairs.
- Turn off gas, electricity and water if you’re told to.
- 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.
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 Melksham
Does Melksham flood?
The last flood the Environment Agency recorded inside the town was in January 2014. 0.7% 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 5.6% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Melksham grades C+ for hazard risk against UK towns.
Which parts of Melksham are at risk of flooding?
From rivers and the sea, the places the Environment Agency warns directly: Bristol Avon (mid) at Melksham. Surface water can collect in low spots anywhere in the town. Check a specific address on GOV.UK’s long-term flood risk service.
When did Melksham last flood?
The recorded flood outlines inside the town run from 1900 to 2014 (18 years); the largest was in 1932. Flood warnings have been issued for parts of the town since 2006, most recently on 24 November 2024.
Is Melksham at risk of surface water flooding?
About 3% of homes are at high risk and 2.6% at medium risk from surface water, against 0.7% 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 Melksham?
Not by the atlas: every 1 km square over Melksham is in the lowest band, where fewer than 1 in 100 homes are expected to be above the action level.
Are there flood warnings in Melksham now?
No flood warning or alert was in force near Melksham at 6 November 2026, 21:29. 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.