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CHazard risk Grade
Flood & hazards in Christchurch · Environment Agency

Heavy rain is Christchurch’s main flood risk: 2.5% of homes, against 1.4% 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. Christchurch grades C for hazard risk: #20 of 30 in Dorset.

1959worst recorded flood121flood warnings since 200610%at low risk
In brief

What stands out about Christchurch’s hazards

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

Rain, more than the river2.5% of homes sit where heavy rain can flood the streets, against 1.4% at risk from rivers and the sea.Remembers 1959Floodwater covered 24 hectares of today’s Christchurch in 1959; 132 of today’s households live inside past flood outlines.The River Avon ran its highest in January 20230.84 m at Knapp Mill on 16 January 2023, 0 cm under the record set in 2023.121 flood warnings since 2006For the parts of Christchurch the Environment Agency warns directly; the most recent on 7 February 2026.
By hazard

What Christchurch faces

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

Rivers and the sea

1.4%of homes at high or medium risk
More than the typical UK town · more than 73% of towns
349 homes by the EA’s own count

Surface water

2.5%of homes at high or medium risk
More than 33% of UK towns
Rivers and sea: 1.4%

Past floods

9years with a recorded flood
Last recorded: February 2014
132 households inside past outlines

The River Avon

0.84 mhighest in winter 2022–23 at Knapp Mill
Highest of 28 winters
Record 0.84 m, January 2023

Flood warnings

121flood warnings since 2006
590 flood alerts for the wider area
Last warning 7 February 2026

Radon

1%of the town in a radon Affected Area
Highest band here: 3–5% of homes
No square 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

Christchurch grades C for hazard risk

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

Homes at high or medium flood risk (1.4%)Fewer than 27% 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 Christchurch

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: 1959Recorded flood: 1979Recorded flood: 1982Recorded flood: 1989Recorded flood: 1990Recorded flood: 2009Recorded flood: 2012Recorded flood: 2013Recorded flood: 2014© OpenStreetMap contributors · EA NaFRA2
HighMediumLowrivers & seaHighMediumLowsurface waterChristchurch’s built-up area

The river and sea risk follows the Christchurch Harbour, the English Channel and the River Allen. 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

1.4% of Christchurch’s homes are at high or medium risk from rivers or the sea

The Environment Agency’s national map, allowing for defences. A further 10% are at low risk.

High risk0.8%of homes · 1 in 30 a year or more211 homes, EA count
Medium risk0.6%of homes · 1 in 30 to 1 in 100138 homes, EA count
Low risk10%of homes · 1 in 100 to 1 in 1,0002,472 homes, EA count
Where Christchurch sits among 3,735 UK towns
35%None
23%Under 0.5%
9%0.5–1%
11%1–2%Christchurch
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; Christchurch has more than 73% of towns.

Towns its size: 112th of 151 from the fewest homes at risk
#TownPeopleHigh or med.
1Dudley West Midlands64,2770%
2Smethwick West Midlands56,3430%
3Bootle Merseyside53,7220%
…
110Paignton Devon67,5091.3%
111Long Eaton Derbyshire37,8151.3%
112Christchurch Dorset48,9731.4%
113Grantham Lincolnshire44,9061.4%
114Bishop's Stortford Hertfordshire40,9161.4%
…
150Tonbridge Kent36,1367.9%
151Exmouth Devon35,5029.8%

UK towns of 34,000 to 69,000 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

Heavy rain puts about 1.8 times as many Christchurch 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.

Surface water2.5%
Rivers and the sea1.4%
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 1.3% at medium risk: roughly 560 households. A further 8.2% face a low risk from surface water. That is more than 33% of UK towns.

~560
households at high or medium risk
8.2%
of homes at low risk
33%
of UK towns have a smaller share
27,976
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

Christchurch has flooded in 9 recorded years since 1959, most of all in 1959

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

  1. 2014January and February 2014: The sea came in3 hectares inside today’s built-up area · This represents flooding in the area in
  2. 2013December 2013: River flooding recordedUnder 1 hectare inside today’s built-up area
  3. 2012January 2012: River flooding recordedUnder 1 hectare inside today’s built-up area · This represents flooding in the area in
  4. 2009February 2009: River flooding recorded4 hectares inside today’s built-up area
  5. 1990February 1990: River flooding recordedUnder 1 hectare inside today’s built-up area · This represents flooding in the area in
  6. 1989December 1989: River flooding recorded1 hectare inside today’s built-up area · Stour Corfe Mullen to Christchurch
Show all 9
  1. 1982March 1982: River flooding recorded2 hectares inside today’s built-up area
  2. 1979December 1979: River flooding recorded6 hectares inside today’s built-up area
  3. 1959January 1959: River flooding recorded24 hectares inside today’s built-up area · Avon & Frome, This represents flooding in the area in
The worst: 195924 ha

Floodwater covered 24 hectares of what is now Christchurch in 1959, the largest flood the record holds here (January).

132 of Christchurch’s households today live inside the outline of a recorded flood.

Since 1959, the largest recorded flood inside the town covered 6 hectares.

River levels

The River Avon in January 2023 rose to its highest level since 1994

The highest level each winter (October to September) at the Environment Agency’s Knapp Mill gauge (Burton), since 1994. The river normally runs between 0.33 m and 0.64 m here.

Highest level each winter, metres
Winter 1994–95: highest 0.78 m · 53 days above the normal rangeWinter 1995–96: highest 0.70 m · 8 days above the normal rangeWinter 1996–97: highest 0.66 m · 2 days above the normal rangeWinter 1997–98: highest 0.78 m · 34 days above the normal rangeWinter 1998–99: highest 0.75 m · 32 days above the normal rangeWinter 1999–00: highest 0.74 m · 36 days above the normal rangeWinter 2000–01: highest 0.82 m on 13 December 2000 · 89 days above the normal rangeWinter 2001–02: highest 0.72 m · 3 days above the normal rangeWinter 2002–03: highest 0.81 m on 2 January 2003 · 67 days above the normal rangeWinter 2003–04: highest 0.65 m · 1 days above the normal rangeWinter 2004–05: highest 0.60 m · 0 days above the normal rangeWinter 2005–06: highest 0.65 m · 1 days above the normal rangeWinter 2006–07: highest 0.75 m · 42 days above the normal rangeWinter 2008–09: highest 0.72 m · 6 days above the normal rangeWinter 2009–10: highest 0.64 m · 1 days above the normal rangeWinter 2010–11: highest 0.50 m · 0 days above the normal rangeWinter 2011–12: highest 0.60 m · 0 days above the normal rangeWinter 2012–13: highest 0.74 m · 24 days above the normal rangeWinter 2013–14: highest 0.82 m on 15 February 2014 · 75 days above the normal rangeWinter 2014–15: highest 0.72 m · 1 days above the normal rangeWinter 2015–16: highest 0.70 m · 8 days above the normal rangeWinter 2016–17: highest 0.50 m · 0 days above the normal rangeWinter 2017–18: highest 0.68 m · 9 days above the normal rangeWinter 2018–19: highest 0.62 m · 0 days above the normal rangeWinter 2019–20: highest 0.78 m · 56 days above the normal rangeWinter 2020–21: highest 0.62 m · 0 days above the normal rangeWinter 2021–22: highest 0.65 m · 1 days above the normal rangeWinter 2022–23: highest 0.84 m on 16 January 2023 · 28 days above the normal range’22–23’00–01’13–14Record 0.84 m, 2023Top of normal range
1994–952022–23
The highest days on record
  • 16 January 20230.84 m
  • 13 December 20000.82 m
  • 15 February 20140.82 m
  • 2 January 20030.81 m
  • 7 February 20140.80 m
  • 9 January 20140.80 m

The River Avon has topped its normal range on 577 days since 1994, most in the winters of 2000–01 and 2013–14. By its highest day, the winter of 2022–23 was the highest of the 28.

Environment Agency Hydrology API, Knapp Mill (station 43118), 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 Christchurch · 121 warnings in 20 years

The Environment Agency has 9 flood warning areas and 4 alert areas reaching into the town; warnings since the service began in 2006.

Now: no flood warnings or alerts for Christchurch (checked 12 November 2026, 16:56). Check for flooding on GOV.UK →
Warnings and alerts each year for areas in Christchurch
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 121 warnings, 48 were for Christchurch Harbour Side and 37 for Lower Stour from Sturminster Marshall to Christchurch. 2014 had the most warnings (18); 2024 the most alerts (76).

The most recent warning was on 7 February 2026.

Show the 13 warning and alert areas
AreaKindSince 2006Now
Christchurch Harbour SideWarning area48None
Lower Stour from Sturminster Marshall to ChristchurchWarning area37None
Lower Avon from Ringwood to ChristchurchWarning area19None
Lower Stour at Jumpers Common and A35 Iford Bridge area, ChristchurchWarning area9None
Lower Stour at Beaulieu Garden Park Home SiteWarning area6None
Dorset coast at ChristchurchWarning area1None
Lower Stour from Longham to ChristchurchWarning area1None
Lower Avon at ChristchurchWarning area0None
Lower Stour at Grove Farm Meadow Holiday ParkWarning area0None
Christchurch HarbourAlert area294None
East coast of DorsetAlert area168None
Lower Avon and tributariesAlert area71None
Lower Stour and tributariesAlert area57None

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 Christchurch are in radon Affected Areas, at the low end

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).

SZ1393: Under 1% of homes above the action levelSZ1394: Under 1% of homes above the action levelSZ1395: Under 1% of homes above the action levelSZ1492: Under 1% of homes above the action levelSZ1493: Under 1% of homes above the action levelSZ1494: Under 1% of homes above the action levelSZ1495: Under 1% of homes above the action levelSZ1592: Under 1% of homes above the action levelSZ1593: Under 1% of homes above the action levelSZ1594: Under 1% of homes above the action levelSZ1595: Under 1% of homes above the action levelSZ1692: Under 1% of homes above the action levelSZ1693: Under 1% of homes above the action levelSZ1694: Under 1% of homes above the action levelSZ1695: Under 1% of homes above the action levelSZ1791: Under 1% of homes above the action levelSZ1792: Under 1% of homes above the action levelSZ1793: Under 1% of homes above the action levelSZ1794: Under 1% of homes above the action levelSZ1891: Under 1% of homes above the action levelSZ1892: Under 1% of homes above the action levelSZ1893: Under 1% of homes above the action levelSZ1894: Under 1% of homes above the action levelSZ1992: Under 1% of homes above the action levelSZ1993: Under 1% of homes above the action levelSZ1994: Under 1% of homes above the action levelSZ2093: Under 1% of homes above the action levelSZ2094: Under 1% of homes above the action levelSZ2193: Under 1% of homes above the action levelSZ2194: Under 1% of homes above the action levelSZ2293: Under 1% of homes above the action levelSZ2294: 3–5% of homes above the action level© OpenStreetMap contributors · BGS/UKHSA
Under 1%3–5%
Share of the town’s area in each band
Under 1% of homes99%
3–5% of homes1%

1% of Christchurch’s built-up area is in a radon Affected Area (1% of homes or more above the action level).

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 Christchurch

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

Bransgore: Hazard risk CBarton on Sea: Hazard risk B−New Milton: Hazard risk B−Bournemouth: Hazard risk B−Ashley: Hazard risk C+Hordle: Hazard risk AWest Parley: Hazard risk B+BransgoreBarton on SeaNew MiltonBournemouthAshleyHordleWest ParleyChristchurch
ABCD
TownPeopleHigh or mediumLowHazard
Christchurch48,9731.4%10%C
Bransgore3,6881.3%2.9%C
Barton on Sea6,7630.3%0.2%B−
New Milton11,8720.1%0.1%B−
Bournemouth196,4530.3%0.4%B−
Ashley7,7300.4%0.5%C+
Hordle1,1580%0%A
West Parley3,6650%0.1%B+

Christchurch has more homes at high or medium risk than any neighbour in the table. Hordle and West Parley have none.

Be ready

Get ready for what Christchurch 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.
  • Christchurch’s warning areas include Lower Stour at Jumpers Common and A35 Iford Bridge area, Christchurch and Lower Stour from Longham to Christchurch.
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 Christchurch
  • 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 Christchurch

Does Christchurch flood?

The last flood the Environment Agency recorded inside the town was in February 2014. 1.4% 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 2.5% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Christchurch grades C for hazard risk against UK towns.

Which parts of Christchurch are at risk of flooding?

From rivers and the sea, the places the Environment Agency warns directly: Christchurch Harbour Side, Lower Stour from Sturminster Marshall to Christchurch, Lower Avon from Ringwood to Christchurch and Lower Stour at Jumpers Common and A35 Iford Bridge area, Christchurch. 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 Christchurch last flood?

The recorded flood outlines inside the town run from 1959 to 2014 (9 years); the largest was in 1959. Flood warnings have been issued for parts of the town since 2006, most recently on 7 February 2026.

Is Christchurch at risk of surface water flooding?

About 1.2% of homes are at high risk and 1.3% at medium risk from surface water, against 1.4% 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 Christchurch?

1% of the town’s built-up area is in a radon Affected Area on the BGS/UKHSA atlas. Most homes are below it; a three-month test is the only way to know.

Are there flood warnings in Christchurch now?

No flood warning or alert was in force near Christchurch at 12 November 2026, 16:56. 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 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.