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River Somer beside the High Street at Midsomer NortonPhoto: David Martin · CC BY-SA 2.0
BHazard risk Grade
Flood & hazards in Midsomer Norton · Environment Agency

In Midsomer Norton, heavy rain puts more homes at risk than rivers or the sea: 2.1%, against under 0.1%

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. Midsomer Norton grades B for hazard risk: #8 of 49 in Somerset.

In brief

What stands out about Midsomer Norton’s hazards

From the Environment Agency’s maps and records and the BGS radon atlas, below.

By hazard

What Midsomer Norton faces

Each hazard against its own yardstick; meters run from low to high on that yardstick.

Not on this page: coastal erosion, subsidence and shrink-swell ground (the British Geological Survey licenses it), groundwater flooding and reservoir failure.
Hazard risk Grade

Midsomer Norton grades B for hazard risk

Flood risk from rivers and the sea, against all UK towns.

Homes at high or medium flood risk (under 0.1%)Fewer than 64% of 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.

Flood map

Where the water goes in Midsomer Norton

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.

Recorded flood: 1954Recorded flood: 1960Recorded flood: 1963Recorded flood: 1965Recorded flood: 1968Recorded flood: 1972Recorded flood: 1974Recorded flood: 1975Recorded flood: 1979Recorded flood: 2016© OpenStreetMap contributors · EA NaFRA2
HighMediumLowrivers & seaHighMediumLowsurface waterMidsomer Norton’s built-up area

The river and sea risk follows the Wellow Brook, the River Somer and the River Cam. Surface-water risk is spread across the town, in dips, underpasses and along small streams, which is why more homes are exposed to it.

Rivers and the sea

Under 0.1% of Midsomer Norton’s homes are at high or medium risk from rivers or the sea

The Environment Agency’s national map, allowing for defences. None are in the low-risk band.

High riskunder 0.1%of homes · 1 in 30 a year or more1 homes, EA count
Medium risk0%of homes · 1 in 30 to 1 in 1000 homes, EA count
Low risk0%of homes · 1 in 100 to 1 in 1,0000 homes, EA count
Where Midsomer Norton sits among 3,735 UK towns
35%None
23%Under 0.5%Midsomer Norton
9%0.5–1%
11%1–2%
11%2–5%
5%5–10%
3%10–20%
2%20% +

Share of each UK town’s homes at high or medium risk from rivers and the sea. 35% of UK towns have none; Midsomer Norton has more than 36% of towns.

Towns its size: 80th of 360 from the fewest homes at risk
#TownPeopleHigh or med.
1Litherland Merseyside18,7520%
2Clifton Greater Manchester17,7480%
3Oswestry Shropshire17,5000%
…
78Shepshed Leicestershire14,873under 0.1%
79Church Village Mid Glamorgan14,162under 0.1%
80Midsomer Norton Somerset13,749under 0.1%
81Churchdown Gloucestershire13,480under 0.1%
82Sheerness Kent13,253under 0.1%
…
359Bentley South Yorkshire12,04440%
360Dunscroft and Hatfield South Yorkshire14,00051%

UK towns of 10,000 to 19,000 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.

Surface water

2.1% of Midsomer Norton’s homes are at high or medium risk from surface water

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.

Surface water2.1%
Rivers and the seaunder 0.1%
0%7%14% of homes

About 1.2% of homes are at high risk of surface-water flooding (a 1 in 30 chance or more each year) and 1% at medium risk: roughly 120 households. A further 5% face a low risk from surface water. That is more than 27% of UK towns.

~120
households at high or medium risk
5%
of homes at low risk
27%
of UK towns have a smaller share
6,930
addresses read on the map

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.

Flood history

Midsomer Norton has flooded in 10 recorded years since 1954, most of all in 1968

Every flood the Environment Agency has mapped inside Midsomer Norton’s built-up area, newest first. The record is fullest for big river floods; small and surface-water floods are often missing.

  1. 2016June 2016: River flooding recorded2 hectares inside today’s built-up area · Riverside Bridge Playing Fields
  2. 1979May 1979: River flooding recorded2 hectares inside today’s built-up area
  3. 1975January 1975: River flooding recorded1 hectare inside today’s built-up area
  4. 1974February 1974: River flooding recorded5 hectares inside today’s built-up area
  5. 1972December 1972: River flooding recorded3 hectares inside today’s built-up area
  6. 1968July 1968: River flooding recorded7 hectares inside today’s built-up area
Show all 10
  1. 1965December 1965: River flooding recorded1 hectare inside today’s built-up area
  2. 1963November 1963: River flooding recordedUnder 1 hectare inside today’s built-up area
  3. 1960December 1960: River flooding recorded1 hectare inside today’s built-up area
  4. 1954November 1954: River flooding recorded1 hectare inside today’s built-up area
The worst: 19687 ha

Floodwater covered 7 hectares of what is now Midsomer Norton in 1968, the largest flood the record holds here (July).

84 of Midsomer Norton’s households today live inside the outline of a recorded flood.

Since 1968, the largest recorded flood inside the town covered 5 hectares.

River levels

The Wellow Brook at Welton: highest 0.89 m, in June 2016

The highest level each winter (October to September) at the Environment Agency’s Welton gauge, since 2007. The river normally runs between 0.00 m and 0.70 m here.

Highest level each winter, metres
Winter 2007–08: highest 0.61 m on 11 January 2008 · 0 days above the normal rangeWinter 2008–09: highest 0.48 m · 0 days above the normal rangeWinter 2010–11: highest 0.26 m · 0 days above the normal rangeWinter 2011–12: highest 0.49 m · 0 days above the normal rangeWinter 2012–13: highest 0.82 m on 25 November 2012 · 3 days above the normal rangeWinter 2013–14: highest 0.51 m · 0 days above the normal rangeWinter 2014–15: highest 0.42 m · 0 days above the normal rangeWinter 2015–16: highest 0.89 m on 17 June 2016 · 1 days above the normal rangeWinter 2016–17: highest 0.60 m on 21 November 2016 · 0 days above the normal rangeWinter 2017–18: highest 0.39 m · 0 days above the normal rangeWinter 2018–19: highest 0.55 m · 0 days above the normal rangeWinter 2019–20: highest 0.46 m · 0 days above the normal rangeWinter 2020–21: highest 0.49 m · 0 days above the normal rangeWinter 2021–22: highest 0.28 m · 0 days above the normal rangeWinter 2022–23: highest 0.69 m on 12 January 2023 · 0 days above the normal rangeWinter 2023–24: highest 0.68 m on 21 February 2024 · 0 days above the normal rangeWinter 2024–25: highest 0.59 m · 0 days above the normal rangeWinter 2025–26: highest 0.44 m · 0 days above the normal range’15–16’12–13’22–23Record 0.89 m, 2016Top of normal range
2007–082025–26
The highest days on record
  • 17 June 20160.89 m
  • 25 November 20120.82 m
  • 12 January 20230.69 m
  • 6 February 20160.68 m
  • 21 February 20240.68 m
  • 4 January 20240.65 m

The Wellow Brook has topped its normal range on 4 days since 2007, most in the winters of 2012–13 and 2015–16. By its highest day, the winter of 2025–26 was the 14th-highest of the 18.

Environment Agency Hydrology API, Welton (station 531107), 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.

Flood warnings

No flood warning or alert is in force for Midsomer Norton · 0 warnings in 20 years

The Environment Agency has 2 flood warning areas and 1 alert area reaching into the town; warnings since the service began in 2006.

Now: no flood warnings or alerts for Midsomer Norton (checked 11 November 2026, 07:28). Check for flooding on GOV.UK →
Warnings and alerts each year for areas in Midsomer Norton
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Flood warning (flooding expected)Flood alert (flooding possible)

None of Midsomer Norton’s 2 flood warning areas has had a flood warning since the service began in 2006.

Show the 3 warning and alert areas
AreaKindSince 2006Now
Wellow Brook and River Somer at Midsomer Norton and Radstock, Thicketmead Bridge and Coombend areasWarning area0None
Wellow Brook and River Somer at Midsomer Norton and Radstock, Riverside, Welton and Mill Road areasWarning area0None
Midford Brook catchmentAlert area27None

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.

Radon

Parts of Midsomer Norton 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).

ST6454: Over 30% of homes above the action levelST6553: 10–30% of homes above the action levelST6554: 10–30% of homes above the action levelST6555: 10–30% of homes above the action levelST6652: Over 30% of homes above the action levelST6653: Over 30% of homes above the action levelST6654: Over 30% of homes above the action levelST6655: 10–30% of homes above the action levelST6752: Over 30% of homes above the action levelST6753: Over 30% of homes above the action levelST6754: Over 30% of homes above the action levelST6755: 10–30% of homes above the action level© OpenStreetMap contributors · BGS/UKHSA
10–30%Over 30%
Share of the town’s area in each band
10–30% of homes39%
Over 30% of homes61%

100% of Midsomer Norton’s built-up area is in a radon Affected Area (1% of homes or more above the action level), and 100% in squares of 5% or more.

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.

Neighbours

Flood risk in the places around Midsomer Norton

Share of homes at high or medium and at low risk from rivers and the sea. Tap a town for its page.

ABCD
TownPeopleHigh or mediumLowHazard
Midsomer Norton13,749under 0.1%0%B
Radstock9,9830.9%2%C
Chilcompton1,8571.9%0.9%C−
Paulton6,502under 0.1%0%B
High Littleton1,6550%0%A
Timsbury2,5060.2%0%B−
Coleford2,2350.2%0.3%B−
Peasedown St John6,6680%0%A

Chilcompton, 1.6 miles south-west, has the most homes at risk around Midsomer Norton (1.9% at high or medium). High Littleton and Peasedown St John have none.

Be ready

Get ready for what Midsomer Norton faces

Free warnings, what to do in a cloudburst, and what to check before you move.

Get the warnings
  • Sign up free for Environment Agency flood warnings by text, call or email.
  • Floodline: 0345 988 1188, 24 hours.
  • Midsomer Norton’s warning areas include Wellow Brook and River Somer at Midsomer Norton and Radstock, Riverside, Welton and Mill Road areas and Wellow Brook and River Somer at Midsomer Norton and Radstock, Thicketmead Bridge and Coombend areas.
Sign up ↗
In a cloudburst
  • 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.
Radon
  • 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%.
UKradon ↗
Before you buy or rent in Midsomer Norton
  • 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.
How to read these numbers

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.

Check the long-term flood risk for an address on GOV.UK →

Questions about flooding and hazards in Midsomer Norton

Does Midsomer Norton flood?

The last flood the Environment Agency recorded inside the town was in June 2016. Under 0.1% 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 2.1% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Midsomer Norton grades B for hazard risk against UK towns.

Which parts of Midsomer Norton are at risk of flooding?

From rivers and the sea, the places the Environment Agency warns directly: Wellow Brook and River Somer at Midsomer Norton and Radstock, Riverside, Welton and Mill Road areas and Wellow Brook and River Somer at Midsomer Norton and Radstock, Thicketmead Bridge and Coombend areas. 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 Midsomer Norton last flood?

The recorded flood outlines inside the town run from 1954 to 2016 (10 years); the largest was in 1968.

Is Midsomer Norton at risk of surface water flooding?

About 1.2% of homes are at high risk and 1% at medium risk from surface water, against under 0.1% 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 Midsomer Norton?

100% of the town’s built-up area is in a radon Affected Area on the BGS/UKHSA atlas, and 100% 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 Midsomer Norton now?

No flood warning or alert was in force near Midsomer Norton at 11 November 2026, 07:28. 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.