Photo: Alan Hunt · CC BY-SA 2.0Rivers and the sea put none of Upper Halliford’s homes at high or medium risk; surface water puts 1.7% at risk
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. Upper Halliford grades B+ for hazard risk.
What stands out about Upper Halliford’s hazards
From the Environment Agency’s maps and records and the BGS radon atlas, below.
What Upper Halliford 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 Thames
Flood warnings
Radon
Upper Halliford grades B+ 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 Upper Halliford
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.
No home in Upper Halliford is in the high or medium band for rivers or the sea. Surface-water risk is spread across the village, in dips, underpasses and along small streams, which is why more homes are exposed to it.
0% of Upper Halliford’s homes are at high or medium risk from rivers or the sea
The Environment Agency’s national map, allowing for defences. A further under 0.1% 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.
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.
1.7% of Upper Halliford’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.
About 0.8% of homes are at high risk of surface-water flooding (a 1 in 30 chance or more each year) and 0.9% at medium risk: roughly 20 households. A further 6.7% face a low risk from surface water. That is more than 19% of UK towns.
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.
Upper Halliford has flooded in 5 recorded years since 1947, most of all in 2002
Every flood the Environment Agency has mapped inside Upper Halliford’s built-up area, newest first. The record is fullest for big river floods; small and surface-water floods are often missing.
- 2013November 2013: River flooding recorded1 hectare inside today’s built-up area
- 2002December 2002: River flooding recorded3 hectares inside today’s built-up area
- 2000January 2000: River flooding recorded1 hectare inside today’s built-up area
- 1968September 1968: River flooding recordedUnder 1 hectare inside today’s built-up area
- 1947January and March 1947: River flooding recordedUnder 1 hectare inside today’s built-up area
Floodwater covered 3 hectares of what is now Upper Halliford in 2002, the largest flood the record holds here (December).
6 of Upper Halliford’s households today live inside the outline of a recorded flood.
Since 2002, the largest recorded flood inside the village covered 1 hectare.
The River Thames at Sunbury Lock: highest 0.92 m, in February 2014
The highest level each winter (October to September) at the Environment Agency’s Sunbury Lock gauge (Sunbury), since 1995. The river normally runs between 0.06 m and 0.30 m here.
- 10 November 20218.43 m
- 28 September 20218.41 m
- 17 May 20218.37 m
- 6 July 20218.36 m
- 1 February 20198.35 m
- 1 November 20188.33 m
The River Thames has topped its normal range on 937 days since 1995, most in the winters of 2023–24 and 2020–21. By its highest day, the winter of 2023–24 was the 9th-highest of the 26.
Environment Agency Hydrology API, Sunbury Lock (station 3101TH), 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 Upper Halliford · 1 warning 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.
Of the 1 warnings, 1 were for River Ash at Ashford and Staines. 2014 had the most warnings (1).
The most recent warning was on 10 February 2014.
Show the 2 warning and alert areas
| Area | Kind | Since 2006 | Now |
|---|---|---|---|
| River Ash at Ashford and Staines | Warning area | 1 | None |
| River Ash in the Borough of Spelthorne | Alert area | 1 | 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.
Upper Halliford 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 Upper Halliford 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 Upper Halliford
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 |
|---|---|---|---|---|
| Upper Halliford | 2,337 | 0% | under 0.1% | B+ |
| Shepperton | 5,917 | 30% | 36% | D− |
| Shepperton Green | 4,358 | 21% | 61% | D− |
| Sunbury-on-Thames | 21,476 | 2.1% | 6% | C− |
| Ashford Common | 8,333 | under 0.1% | 37% | B |
| Walton-on-Thames | 27,016 | 7.5% | 13% | D |
| Weybridge | 15,918 | 3.9% | 1.8% | D |
| Ashford | 22,823 | 0.3% | 9% | B− |
Shepperton, 0.8 miles south-west, has the most homes at risk around Upper Halliford (30% at high or medium).
Get ready for what Upper Halliford 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.
- Upper Halliford’s warning areas include River Ash at Ashford and Staines.
- 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 Upper Halliford
Does Upper Halliford flood?
The last flood the Environment Agency recorded inside the village was in November 2013. 0% 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 1.7% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Upper Halliford grades B+ for hazard risk against UK towns.
Which parts of Upper Halliford are at risk of flooding?
From rivers and the sea, the places the Environment Agency warns directly: River Ash at Ashford and Staines. 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 Upper Halliford last flood?
The recorded flood outlines inside the village run from 1947 to 2013 (5 years); the largest was in 2002. Flood warnings have been issued for parts of the village since 2006, most recently on 10 February 2014.
Is Upper Halliford at risk of surface water flooding?
About 0.8% of homes are at high risk and 0.9% at medium risk from surface water, against 0% 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 Upper Halliford?
Not by the atlas: every 1 km square over Upper Halliford 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 Upper Halliford now?
No flood warning or alert was in force near Upper Halliford at 6 November 2026, 02:53. 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.