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D−Hazard risk Grade
Flood & hazards in Caversham · Environment Agency

13% of Caversham’s homes are at high or medium risk from rivers or the sea, more than in 96% 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. Caversham grades D− for hazard risk: #28 of 30 in Berkshire.

1947worst recorded flood5flood warnings since 2006100%in a radon Affected Area
In brief

What stands out about Caversham’s hazards

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

A river town13% of homes are at high or medium risk from rivers or the sea, more than 96% of UK towns.Remembers 1947Floodwater covered 87 hectares of today’s Caversham in 1947; 2,392 of today’s households live inside past flood outlines.5 flood warnings since 2006For the parts of Caversham the Environment Agency warns directly; the most recent on 5 January 2024.Radon in parts60% of the town is in 1 km squares where 5% or more of homes may be above the radon action level.
By hazard

What Caversham faces

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

Rivers and the sea

13%of homes at high or medium risk
More than the typical UK town · more than 96% of towns
1,748 homes by the EA’s own count

Surface water

2.2%of homes at high or medium risk
More than 29% of UK towns
Rivers and sea: 13%

Past floods

8years with a recorded flood
Last recorded: November 2013
2,392 households inside past outlines

The River Kennet

0.23 mhighest in winter 2025–26 at Blakes Lock
34th-highest of 34 winters
Record 0.80 m, December 2000

Flood warnings

5flood warnings since 2006
39 flood alerts for the wider area
Last warning 5 January 2024

Radon

100%of the town in a radon Affected Area
Highest band here: 5–10% of homes
60% in squares of 5% or more
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

Caversham grades D− for hazard risk

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

Homes at high or medium flood risk (13%)Fewer than 4% 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 Caversham

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: 1947Recorded flood: 1974Recorded flood: 1977Recorded flood: 1992Recorded flood: 2000Recorded flood: 2002Recorded flood: 2007Recorded flood: 2013© OpenStreetMap contributors · EA NaFRA2
HighMediumLowrivers & seaHighMediumLowsurface waterCaversham’s built-up area

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

Rivers and the sea

13% of Caversham’s homes are at high or medium risk from rivers or the sea

The Environment Agency’s national map, allowing for defences. A further 7.1% are at low risk.

High risk2.8%of homes · 1 in 30 a year or more384 homes, EA count
Medium risk9.9%of homes · 1 in 30 to 1 in 1001,364 homes, EA count
Low risk7.1%of homes · 1 in 100 to 1 in 1,000983 homes, EA count
Where Caversham 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%Caversham
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; Caversham has more than 96% of towns.

Towns its size: 215th of 219 from the fewest homes at risk
#TownPeopleHigh or med.
1Grays Essex44,3400%
2Borehamwood Hertfordshire39,7600%
3Chadderton Greater Manchester37,6020%
…
213Tonbridge Kent36,1367.9%
214Exmouth Devon35,5029.8%
215Caversham Berkshire33,03813%
216Cleethorpes Lincolnshire29,66027%
217Egham Surrey28,00329%
218Wisbech Cambridgeshire26,80043%
219Spalding Lincolnshire30,55284%

UK towns of 23,000 to 46,000 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

Rivers and the sea, more than heavy rain, are Caversham’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 water2.2%
Rivers and the sea13%
0%10.5%21% of homes

About 0.9% of homes are at high risk of surface-water flooding (a 1 in 30 chance or more each year) and 1.3% at medium risk: roughly 300 households. A further 4.1% face a low risk from surface water. That is more than 29% of UK towns.

~300
households at high or medium risk
4.1%
of homes at low risk
29%
of UK towns have a smaller share
15,425
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

Caversham has flooded in 8 recorded years since 1947, most of all in 1947

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

  1. 2013November 2013: River flooding recorded7 hectares inside today’s built-up area
  2. 2007July 2007: River flooding recorded5 hectares inside today’s built-up area
  3. 2002December 2002: River flooding recorded28 hectares inside today’s built-up area
  4. 2000January 2000: River flooding recorded7 hectares inside today’s built-up area
  5. 1992January 1992: River flooding recorded1 hectare inside today’s built-up area
  6. 1977January 1977: River flooding recorded3 hectares inside today’s built-up area
Show all 8
  1. 1974January 1974: River flooding recorded1 hectare inside today’s built-up area
  2. 1947January 1947: River flooding recorded87 hectares inside today’s built-up area
The worst: 194787 ha

Floodwater covered 87 hectares of what is now Caversham in 1947, the largest flood the record holds here (January).

2,392 of Caversham’s households today live inside the outline of a recorded flood.

Since 1947, the largest recorded flood inside the town covered 28 hectares.

River levels

The River Kennet at Blakes Lock: highest 0.80 m, in December 2000

The highest level each winter (October to September) at the Environment Agency’s Blakes Lock gauge (Reading), since 1991. The river normally runs between 0.00 m and 0.20 m here.

Highest level each winter, metres
Winter 1991–92: highest 0.44 m · 15 days above the normal rangeWinter 1992–93: highest 0.31 m · 26 days above the normal rangeWinter 1993–94: highest 0.26 m · 20 days above the normal rangeWinter 1994–95: highest 0.39 m · 44 days above the normal rangeWinter 1995–96: highest 0.37 m · 53 days above the normal rangeWinter 1996–97: highest 0.43 m · 42 days above the normal rangeWinter 1997–98: highest 0.40 m · 40 days above the normal rangeWinter 1998–99: highest 0.44 m · 66 days above the normal rangeWinter 1999–00: highest 0.67 m on 26 October 1999 · 43 days above the normal rangeWinter 2000–01: highest 0.82 m on 14 December 2000 · 110 days above the normal rangeWinter 2002–03: highest 0.73 m on 3 January 2003 · 45 days above the normal rangeWinter 2003–04: highest 0.41 m · 24 days above the normal rangeWinter 2004–05: highest 0.32 m · 18 days above the normal rangeWinter 2005–06: highest 0.34 m · 23 days above the normal rangeWinter 2006–07: highest 0.39 m · 49 days above the normal rangeWinter 2007–08: highest 0.32 m · 36 days above the normal rangeWinter 2008–09: highest 0.37 m · 28 days above the normal rangeWinter 2009–10: highest 0.37 m · 104 days above the normal rangeWinter 2010–11: highest 0.30 m · 23 days above the normal rangeWinter 2011–12: highest 0.28 m · 9 days above the normal rangeWinter 2012–13: highest 0.39 m · 71 days above the normal rangeWinter 2013–14: highest 0.78 m on 9 February 2014 · 100 days above the normal rangeWinter 2014–15: highest 0.30 m · 40 days above the normal rangeWinter 2015–16: highest 0.32 m · 49 days above the normal rangeWinter 2016–17: highest 0.29 m · 28 days above the normal rangeWinter 2017–18: highest 0.31 m · 60 days above the normal rangeWinter 2018–19: highest 0.33 m · 33 days above the normal rangeWinter 2019–20: highest 0.34 m · 28 days above the normal rangeWinter 2020–21: highest 0.33 m · 20 days above the normal rangeWinter 2021–22: highest 0.35 m · 82 days above the normal rangeWinter 2022–23: highest 0.37 m · 58 days above the normal rangeWinter 2023–24: highest 0.71 m on 7 January 2024 · 64 days above the normal rangeWinter 2024–25: highest 0.34 m · 21 days above the normal rangeWinter 2025–26: highest 0.23 m · 6 days above the normal range’00–01’13–14’02–03Record 0.80 m, 2000Top of normal range
1991–922025–26
The highest days on record
  • 14 December 20000.82 m
  • 9 February 20140.78 m
  • 3 January 20030.73 m
  • 7 January 20240.71 m
  • 8 November 20000.70 m
  • 26 October 19990.67 m

The River Kennet has topped its normal range on 1,478 days since 1991, most in the winters of 2000–01 and 2009–10. By its highest day, the winter of 2025–26 was the 34th-highest of the 34.

Environment Agency Hydrology API, Blakes Lock (station 2298TH), 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 Caversham · 5 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 Caversham (checked 4 November 2026, 18:06). Check for flooding on GOV.UK →
Warnings and alerts each year for areas in Caversham
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)

Of the 5 warnings, 4 were for Properties closest to the River Thames from Scours Lane, Reading to Caversham Lakes and 1 for River Thames at Reading and Caversham. 2014 had the most warnings (2); 2013 the most alerts (5).

The most recent warning was on 5 January 2024.

Show the 3 warning and alert areas
AreaKindSince 2006Now
Properties closest to the River Thames from Scours Lane, Reading to Caversham LakesWarning area4None
River Thames at Reading and CavershamWarning area1None
River Thames from Mapledurham to SonningAlert area39None

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 Caversham are in radon Affected Areas, up to the 5–10% 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).

SU6974: 3–5% of homes above the action levelSU6975: 3–5% of homes above the action levelSU6976: 3–5% of homes above the action levelSU7074: 3–5% of homes above the action levelSU7075: 5–10% of homes above the action levelSU7076: 5–10% of homes above the action levelSU7174: 3–5% of homes above the action levelSU7175: 5–10% of homes above the action levelSU7176: 5–10% of homes above the action levelSU7177: 5–10% of homes above the action levelSU7274: 3–5% of homes above the action levelSU7275: 5–10% of homes above the action levelSU7276: 1–3% of homes above the action levelSU7277: 3–5% of homes above the action levelSU7374: 3–5% of homes above the action levelSU7375: 5–10% of homes above the action levelSU7376: 3–5% of homes above the action level© OpenStreetMap contributors · BGS/UKHSA
1–3%3–5%5–10%
Share of the town’s area in each band
1–3% of homes10%
3–5% of homes30%
5–10% of homes60%

100% of Caversham’s built-up area is in a radon Affected Area (1% of homes or more above the action level), and 60% in squares of 5% or more, mostly on the north side of the town.

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 Caversham

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

Reading: Hazard risk CSonning: Hazard risk C+Sonning Common: Hazard risk AWoodley: Hazard risk B−Charvil: Hazard risk DLower Shiplake: Hazard risk D−Twyford: Hazard risk C+ReadingSonningSonning CommonWoodleyCharvilLower ShiplakeTwyfordCaversham
ABCD
TownPeopleHigh or mediumLowHazard
Caversham33,03813%7.1%D−
Reading203,7891%3.2%C
Sonning1,6150.4%0.1%C+
Sonning Common5,2640%0%A
Woodley28,0190.2%0.3%B−
Charvil3,1584.3%29%D
Lower Shiplake1,08614%32%D−
Twyford8,0720.7%1.7%C+

Lower Shiplake, 4.4 miles north-east, has the most homes at risk around Caversham (14% at high or medium). Sonning Common has none.

Be ready

Get ready for what Caversham 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.
  • Caversham’s warning areas include River Thames at Reading and Caversham and Properties closest to the River Thames from Scours Lane, Reading to Caversham Lakes.
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 Caversham
  • 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 Caversham

Does Caversham flood?

The last flood the Environment Agency recorded inside the town was in November 2013. 13% 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 2.2% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Caversham grades D− for hazard risk against UK towns.

Which parts of Caversham are at risk of flooding?

From rivers and the sea, the places the Environment Agency warns directly: Properties closest to the River Thames from Scours Lane, Reading to Caversham Lakes and River Thames at Reading and Caversham. 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 Caversham last flood?

The recorded flood outlines inside the town run from 1947 to 2013 (8 years); the largest was in 1947. Flood warnings have been issued for parts of the town since 2006, most recently on 5 January 2024.

Is Caversham at risk of surface water flooding?

About 0.9% of homes are at high risk and 1.3% at medium risk from surface water, against 13% 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 Caversham?

100% of the town’s built-up area is in a radon Affected Area on the BGS/UKHSA atlas, and 60% 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 Caversham now?

No flood warning or alert was in force near Caversham at 4 November 2026, 18:06. 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.