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Old Post Office Thorney CambsPhoto: Russ Hamer · CC BY-SA 3.0
D−Hazard risk Grade
Flood & hazards in Thorney · Environment Agency

Thorney is a river town: 29% of its homes are at high or medium risk from rivers or the sea, more than in 99% of UK towns

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. Hazard risk puts Thorney at D−.

In brief

What stands out about Thorney’s hazards

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

By hazard

What Thorney 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

Thorney grades D− for hazard risk

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

Homes at high or medium flood risk (29%)Fewer than 1% 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 Thorney

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: 1947© OpenStreetMap contributors · EA NaFRA2
HighMediumLowrivers & seaHighMediumLowsurface waterThorney’s built-up area

The river and sea risk follows the The Wash, the River Witham and the River Welland. Surface-water risk is patchier: dips, underpasses and small streams.

Rivers and the sea

29% of Thorney’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 risk0%of homes · 1 in 30 a year or more0 homes, EA count
Medium risk29%of homes · 1 in 30 to 1 in 100214 homes, EA count
Low risk0%of homes · 1 in 100 to 1 in 1,0000 homes, EA count
Where Thorney sits among 3,735 UK towns
35%None
23%Under 0.5%
9%0.5–1%
11%1–2%
11%2–5%
5%5–10%
3%10–20%
2%20% +Thorney

Share of each UK town’s homes at high or medium risk from rivers and the sea. 35% of UK towns have none; Thorney has more than 99% of towns.

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

Rivers and the sea, more than heavy rain, are Thorney’s flood risk

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 water5.3%
Rivers and the sea29%
0%17.5%35% of homes

About 2.1% of homes are at high risk of surface-water flooding (a 1 in 30 chance or more each year) and 3.2% at medium risk: roughly 40 households. A further 8.3% face a low risk from surface water. That is more than 72% of UK towns.

~40
households at high or medium risk
8.3%
of homes at low risk
72%
of UK towns have a smaller share
865
addresses read on the map

Our estimate: every address in the village (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

Thorney has flooded in 1 recorded year since 1947

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

  1. 1947March 1947: River flooding recorded11 hectares inside today’s built-up area
The worst: 194711 ha

Floodwater covered 11 hectares of what is now Thorney in 1947, the largest flood the record holds here (March).

126 of Thorney’s households today live inside the outline of a recorded flood.

Flood warnings

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

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

Now: no flood warnings or alerts for Thorney (checked 11 November 2026, 19:56). Check for flooding on GOV.UK →
Warnings and alerts each year for areas in Thorney
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 Thorney’s 1 flood warning area has had a flood warning since the service began in 2006.

Show the 2 warning and alert areas
AreaKindSince 2006Now
Long Sutton to Newborough and surrounding areasWarning area0None
Far extent of Tidal Flooding from the Wash and Tidal EstuariesAlert area12None

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

Thorney 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).

TF2704: Under 1% of homes above the action levelTF2705: Under 1% of homes above the action levelTF2803: Under 1% of homes above the action levelTF2804: Under 1% of homes above the action levelTF2805: Under 1% of homes above the action levelTF2903: Under 1% of homes above the action levelTF2904: Under 1% of homes above the action level© OpenStreetMap contributors · BGS/UKHSA
Under 1%
Share of the village’s area in each band
Under 1% of homes100%

Every 1 km square over Thorney 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.

Neighbours

Flood risk in the places around Thorney

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
Thorney1,65529%0%D−
Eye5,4194.6%4.5%D
Whittlesey13,8333.9%0%D
Coates and Eastrea2,3132%0%C−
Crowland4,61918%0.6%D−
Newborough1,46937%3.1%D−
Parson Drove1,19726%21%D−
Peterborough190,5920.5%1%C+

Newborough, 5.1 miles west, has the most homes at risk around Thorney (37% at high or medium).

Be ready

Get ready for what Thorney 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.
  • Thorney’s warning areas include Long Sutton to Newborough and surrounding 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.
When the river rises
  • 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.
Before you buy or rent in Thorney
  • 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.
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 Thorney

Does Thorney flood?

The last flood the Environment Agency recorded inside the village was in March 1947. 29% 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 5.3% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Thorney grades D− for hazard risk against UK towns.

Which parts of Thorney are at risk of flooding?

From rivers and the sea, the places the Environment Agency warns directly: Long Sutton to Newborough and surrounding areas. Surface water can collect in low spots anywhere in the village. Check a specific address on GOV.UK’s long-term flood risk service.

When did Thorney last flood?

The recorded flood outlines inside the village run from 1947 to 1947 (1 years); the largest was in 1947.

Is Thorney at risk of surface water flooding?

About 2.1% of homes are at high risk and 3.2% at medium risk from surface water, against 29% 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 Thorney?

Not by the atlas: every 1 km square over Thorney 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 Thorney now?

No flood warning or alert was in force near Thorney at 11 November 2026, 19:56. 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 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.