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CHazard risk Grade
Flood & hazards in Brent · Environment Agency

Surface water, more than the river, is Brent’s flood risk: 15% of homes, against 1.5% 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. Hazard risk puts Brent at C: #24 of 33 in London.

1977worst recorded flood7flood warnings since 20062.1%at low risk
In brief

What stands out about Brent’s hazards

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

Rain, more than the river15% of homes sit where heavy rain can flood the streets, against 1.5% at risk from rivers and the sea.Remembers 1977Floodwater covered 15 hectares of today’s Brent in 1977; 92 of today’s households live inside past flood outlines.The Silk Stream ran its 5th-highest in July 20251.77 m at Colindale on 19 July 2025, 66 cm under the record set in 1992.7 flood warnings since 2006For the parts of Brent the Environment Agency warns directly; the most recent on 15 July 2024.
By hazard

What Brent faces

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

Rivers and the sea

1.5%of homes at high or medium risk
More than the typical UK town · more than 74% of towns
2,341 homes by the EA’s own count

Surface water

15%of homes at high or medium risk
More than 97% of UK towns
Rivers and sea: 1.5%

Past floods

3years with a recorded flood
Last recorded: August 2023
92 households inside past outlines

The Silk Stream

1.64 mhighest in winter 2025–26 at Colindale
10th-highest of 36 winters
Record 2.43 m, September 1992

Flood warnings

7flood warnings since 2006
106 flood alerts for the wider area
Last warning 15 July 2024

Radon

0%of the borough in a radon Affected Area
Highest band here: Under 1% 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

Brent grades C for hazard risk

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

Homes at high or medium flood risk (1.5%)Fewer than 26% 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 Brent

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: 1977Recorded flood: 2007Recorded flood: 2023© OpenStreetMap contributors · EA NaFRA2
HighMediumLowrivers & seaHighMediumLowsurface waterBrent’s built-up area

The river and sea risk follows the Silk Stream; Dollis Brook; Deans Brook; Edgware Brook; Mutton Brook; Wealdstone Brook; Wembley Brook, the River Brent and the Wealdstone Brook. Surface-water risk is spread across the borough, in dips, underpasses and along small streams, which is why more homes are exposed to it.

Rivers and the sea

1.5% of Brent’s homes are at high or medium risk from rivers or the sea

The Environment Agency’s national map, allowing for defences. A further 2.1% are at low risk.

High risk0.2%of homes · 1 in 30 a year or more750 homes, EA count
Medium risk1.3%of homes · 1 in 30 to 1 in 1001,591 homes, EA count
Low risk2.1%of homes · 1 in 100 to 1 in 1,0003,405 homes, EA count
Where Brent sits among 3,735 UK towns
35%None
23%Under 0.5%
9%0.5–1%
11%1–2%Brent
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; Brent has more than 74% of towns.

Towns its size: 25th of 37 from the fewest homes at risk
#TownPeopleHigh or med.
1Southwark London307,0760%
2Newham London351,065under 0.1%
3Havering London259,4010.1%
…
23Bristol Bristol425,1961.3%
24Redbridge London309,5091.4%
25Brent London340,6111.5%
26Waltham Forest London278,1291.6%
27Southampton Hampshire249,6331.8%
…
36Nottingham Nottinghamshire299,7863.6%
37Kingston upon Hull East Riding of Yorkshire270,8166.3%

UK towns of 238,000 to 477,000 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 9.7 times as many Brent 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 water15%
Rivers and the sea1.5%
0%14%28% of homes

About 8.8% of homes are at high risk of surface-water flooding (a 1 in 30 chance or more each year) and 5.7% at medium risk: roughly 17,540 households. A further 12% face a low risk from surface water. That is more than 97% of UK towns.

~17,540
households at high or medium risk
12%
of homes at low risk
97%
of UK towns have a smaller share
168,630
addresses read on the map

Our estimate: every address in the borough (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

Brent has flooded in 3 recorded years since 1977, most of all in 1977

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

  1. 2023August 2023: River flooding recorded2 hectares inside today’s built-up area
  2. 2007July 2007: River flooding recorded6 hectares inside today’s built-up area
  3. 1977January 1977: River flooding recorded15 hectares inside today’s built-up area
The worst: 197715 ha

Floodwater covered 15 hectares of what is now Brent in 1977, the largest flood the record holds here (January).

92 of Brent’s households today live inside the outline of a recorded flood.

Since 1977, the largest recorded flood inside the borough covered 6 hectares.

River levels

The Silk Stream in July 2025 rose to its 5th-highest level since 1990

The highest level each winter (October to September) at the Environment Agency’s Colindale gauge (Hendon), since 1990. The river normally runs between 0.10 m and 1.25 m here.

Highest level each winter, metres
Winter 1990–91: highest 1.32 m · 1 days above the normal rangeWinter 1991–92: highest 2.43 m on 23 September 1992 · 3 days above the normal rangeWinter 1992–93: highest 1.66 m · 2 days above the normal rangeWinter 1993–94: highest 1.55 m · 3 days above the normal rangeWinter 1994–95: highest 1.24 m · 0 days above the normal rangeWinter 1995–96: highest 1.29 m · 1 days above the normal rangeWinter 1996–97: highest 1.73 m on 26 June 1997 · 1 days above the normal rangeWinter 1997–98: highest 0.80 m · 0 days above the normal rangeWinter 1998–99: highest 1.41 m · 2 days above the normal rangeWinter 1999–00: highest 1.49 m · 1 days above the normal rangeWinter 2000–01: highest 2.01 m on 30 October 2000 · 3 days above the normal rangeWinter 2001–02: highest 1.52 m · 2 days above the normal rangeWinter 2002–03: highest 1.13 m · 0 days above the normal rangeWinter 2003–04: highest 1.15 m · 0 days above the normal rangeWinter 2004–05: highest 0.86 m · 0 days above the normal rangeWinter 2005–06: highest 1.30 m · 1 days above the normal rangeWinter 2006–07: highest 1.70 m on 20 July 2007 · 1 days above the normal rangeWinter 2007–08: highest 1.29 m · 1 days above the normal rangeWinter 2008–09: highest 1.82 m on 27 June 2009 · 2 days above the normal rangeWinter 2009–10: highest 1.30 m · 1 days above the normal rangeWinter 2010–11: highest 1.37 m · 2 days above the normal rangeWinter 2011–12: highest 1.43 m · 1 days above the normal rangeWinter 2012–13: highest 1.24 m · 0 days above the normal rangeWinter 2013–14: highest 1.52 m · 2 days above the normal rangeWinter 2014–15: highest 2.20 m on 26 August 2015 · 2 days above the normal rangeWinter 2015–16: highest 1.65 m · 1 days above the normal rangeWinter 2016–17: highest 1.10 m · 0 days above the normal rangeWinter 2017–18: highest 0.93 m · 0 days above the normal rangeWinter 2018–19: highest 1.51 m · 1 days above the normal rangeWinter 2019–20: highest 1.39 m · 2 days above the normal rangeWinter 2020–21: highest 1.57 m · 4 days above the normal rangeWinter 2021–22: highest 1.16 m · 0 days above the normal rangeWinter 2022–23: highest 1.36 m · 2 days above the normal rangeWinter 2023–24: highest 1.55 m · 2 days above the normal rangeWinter 2024–25: highest 1.77 m on 19 July 2025 · 1 days above the normal rangeWinter 2025–26: highest 1.64 m · 2 days above the normal range’91–92’14–15’00–01Record 2.43 m, 1992Top of normal range
1990–912025–26
The highest days on record
  • 23 September 19922.43 m
  • 26 August 20152.20 m
  • 30 October 20002.01 m
  • 27 June 20091.82 m
  • 19 July 20251.77 m
  • 26 June 19971.73 m

The Silk Stream has topped its normal range on 47 days since 1990, most in the winters of 2020–21 and 1991–92. By its highest day, the winter of 2025–26 was the 10th-highest of the 36.

Environment Agency Hydrology API, Colindale (station 3829TH), 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 Brent · 7 warnings in 20 years

The Environment Agency has 3 flood warning areas and 2 alert areas reaching into the borough; warnings since the service began in 2006.

Now: no flood warnings or alerts for Brent (checked 7 November 2026, 01:59). Check for flooding on GOV.UK →
Warnings and alerts each year for areas in Brent
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)

The warning area covering the most of Brent, River Brent in the London Borough of Brent, has not had a flood warning since 2006. Of the 7 warnings, 6 were for Wealdstone Brook at Kenton and 1 for Kenton Brook at Kenton.

2016 had the most warnings (2). The most recent warning was on 15 July 2024.

Show the 5 warning and alert areas
AreaKindSince 2006Now
Wealdstone Brook at KentonWarning area6None
Kenton Brook at KentonWarning area1None
River Brent in the London Borough of BrentWarning area0None
Silk Stream and the Deans, Edgware, Dollis, Mutton, Wembley and Wealdstone BrooksAlert area79None
River Brent from Hendon to BrentfordAlert 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

Brent 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).

TQ1585: Under 1% of homes above the action levelTQ1586: Under 1% of homes above the action levelTQ1684: Under 1% of homes above the action levelTQ1685: Under 1% of homes above the action levelTQ1686: Under 1% of homes above the action levelTQ1687: Under 1% of homes above the action levelTQ1688: Under 1% of homes above the action levelTQ1782: Under 1% of homes above the action levelTQ1783: Under 1% of homes above the action levelTQ1784: Under 1% of homes above the action levelTQ1785: Under 1% of homes above the action levelTQ1786: Under 1% of homes above the action levelTQ1787: Under 1% of homes above the action levelTQ1788: Under 1% of homes above the action levelTQ1882: Under 1% of homes above the action levelTQ1883: Under 1% of homes above the action levelTQ1884: Under 1% of homes above the action levelTQ1885: Under 1% of homes above the action levelTQ1886: Under 1% of homes above the action levelTQ1887: Under 1% of homes above the action levelTQ1888: Under 1% of homes above the action levelTQ1889: Under 1% of homes above the action levelTQ1982: Under 1% of homes above the action levelTQ1983: Under 1% of homes above the action levelTQ1984: Under 1% of homes above the action levelTQ1985: Under 1% of homes above the action levelTQ1986: Under 1% of homes above the action levelTQ1987: Under 1% of homes above the action levelTQ1988: Under 1% of homes above the action levelTQ1989: Under 1% of homes above the action levelTQ1990: Under 1% of homes above the action levelTQ2082: Under 1% of homes above the action levelTQ2083: Under 1% of homes above the action levelTQ2084: Under 1% of homes above the action levelTQ2085: Under 1% of homes above the action levelTQ2086: Under 1% of homes above the action levelTQ2087: Under 1% of homes above the action levelTQ2088: Under 1% of homes above the action levelTQ2089: Under 1% of homes above the action levelTQ2090: Under 1% of homes above the action levelTQ2182: Under 1% of homes above the action levelTQ2183: Under 1% of homes above the action levelTQ2184: Under 1% of homes above the action levelTQ2185: Under 1% of homes above the action levelTQ2186: Under 1% of homes above the action levelTQ2187: Under 1% of homes above the action levelTQ2188: Under 1% of homes above the action levelTQ2189: Under 1% of homes above the action levelTQ2282: Under 1% of homes above the action levelTQ2283: Under 1% of homes above the action levelTQ2284: Under 1% of homes above the action levelTQ2285: Under 1% of homes above the action levelTQ2286: Under 1% of homes above the action levelTQ2287: Under 1% of homes above the action levelTQ2382: Under 1% of homes above the action levelTQ2383: Under 1% of homes above the action levelTQ2384: Under 1% of homes above the action levelTQ2385: Under 1% of homes above the action levelTQ2386: Under 1% of homes above the action levelTQ2482: Under 1% of homes above the action levelTQ2483: Under 1% of homes above the action levelTQ2484: Under 1% of homes above the action levelTQ2485: Under 1% of homes above the action levelTQ2582: Under 1% of homes above the action levelTQ2583: Under 1% of homes above the action levelTQ2584: Under 1% of homes above the action levelTQ2683: Under 1% of homes above the action level© OpenStreetMap contributors · BGS/UKHSA
Under 1%
Share of the borough’s area in each band
Under 1% of homes100%

Every 1 km square over Brent 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 Brent

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

Ealing: Hazard risk C+Harrow: Hazard risk CBarnet: Hazard risk CCamden: Hazard risk AKensington and Chelsea: Hazard risk BHammersmith and Fulham: Hazard risk BWestminster: Hazard risk AEalingHarrowBarnetCamdenKensington and ChelseaHammersmith and FulhamWestminsterBrent
ABCD
TownPeopleHigh or mediumLowHazard
Brent340,6111.5%2.1%C
Ealing367,2710.6%0.8%C+
Harrow260,5341.3%1.8%C
Barnet388,5721.2%1.5%C
Camden209,3420%0%A
Kensington and Chelsea143,348under 0.1%0%B
Hammersmith and Fulham182,187under 0.1%0%B
Westminster203,5710%0%A

Brent has more homes at high or medium risk than any neighbour in the table. Camden and Westminster have none.

Be ready

Get ready for what Brent 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.
  • Brent’s warning areas include River Brent in the London Borough of Brent and Wealdstone Brook at Kenton.
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 Brent
  • 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 Brent

Does Brent flood?

The last flood the Environment Agency recorded inside the borough was in August 2023. 1.5% 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 15% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Brent grades C for hazard risk against UK towns.

Which parts of Brent are at risk of flooding?

From rivers and the sea, the places the Environment Agency warns directly: Wealdstone Brook at Kenton, Kenton Brook at Kenton and River Brent in the London Borough of Brent. Surface water can collect in low spots anywhere in the borough. Check a specific address on GOV.UK’s long-term flood risk service.

When did Brent last flood?

The recorded flood outlines inside the borough run from 1977 to 2023 (3 years); the largest was in 1977. Flood warnings have been issued for parts of the borough since 2006, most recently on 15 July 2024.

Is Brent at risk of surface water flooding?

About 8.8% of homes are at high risk and 5.7% at medium risk from surface water, against 1.5% 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 Brent?

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

No flood warning or alert was in force near Brent at 7 November 2026, 01:59. 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.