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Does Harrow flood?

Greater London
45postcodes in the EA rivers-and-sea dataset
12river gauges within 10 km
15years with a mapped flood record within 5 km
🏠 Thinking of buying in Harrow? Get the detailed Property Flood-Risk Report for any Harrow postcode — official risk band, recorded floods since 1703, warning history, river behaviour and nearby storm overflows. £19 one-off, instant. Learn more →

What the Environment Agency's rivers-and-sea flood-risk data says about Harrow

Ordnance Survey places 45 postcodes in Harrow in the Environment Agency's rivers-and-sea flood-risk dataset (Risk of Flooding from Rivers and Sea). Each postcode is counted once, under the worst band any of its properties reaches; together they hold 607 properties in the EA dataset's likelihood bands.

EA likelihood bandPostcodes (worst band)Properties in the EA datasetof which homes
High84641
Medium12109100
Low24421390
Very low13114
All bands45607545

This dataset covers flooding from rivers and the sea only — one of five flood sources. Surface water, groundwater, sewers and reservoirs are assessed separately, so a postcode missing from it is not proof that a place cannot flood. The band describes the land around properties (allowing for defences), not any single address and not today's conditions.

Rivers and live river levels near Harrow

Environment Agency gauges within 10 km of Harrow watch Yeading Brook, The Roxbourne, River Pinn, Yeading Brook (Eastern Arm), Wealdstone Brook.

Distances are from the middle of Harrow's at-risk postcodes. Tidal and structure gauges are shown as readings only — the tide and sluice gates move them, not floods. A gauge with no recent reading shows no level.

The watercourse nearest Harrow

The nearest watercourse on the river map is an unnamed stream, about 640 m from the middle of Harrow's at-risk postcodes. It flows into Yeading Brook about 4.2 km downstream.

A gauge downstream shows water that has already passed this point; one upstream sees it first. Distances along the river are from the point on an unnamed stream nearest the middle of Harrow's at-risk postcodes. From Ordnance Survey’s river map (OS Open Rivers), which leaves out small streams, ditches and culverts, so a nearer one may exist. This describes where water goes on the map; it says nothing about flooding at any address. Contains OS data © Crown copyright and database rights 2026.

Flood warning areas near Harrow

26 Environment Agency flood warning areas lie within 10 km of Harrow. The EA has issued 364 flood warnings and alerts for them since 2006, most recently on 24 Oct 2026.

Recorded floods near Harrow

Floods whose mapped extent (EA Recorded Flood Outlines) reached within ~5 km of Harrow, most recent first. Records, not floods: no outline on the record is not evidence a place has not flooded. See them on the map →

…and 12 earlier recorded floods on the map.

Rainfall near Harrow

Harrow gets about 675 mm of rain a year on average (wettest month November, 73 mm; driest March, 43 mm). That is 42% drier than the UK as a whole, which averages 1,163 mm a year. Source: Met Office HadUK-Grid 1991–2020 (5 km grid), 0.4 km from the place centre.

At-risk postcodes in Harrow

Every postcode Ordnance Survey places in Harrow that appears in the EA's rivers-and-sea dataset, worst band first. Each links to its own flood-risk page.

High likelihood (8)

HA2 6AAHA2 7LDHA2 7RAHA2 7RHHA2 9EYHA2 9HLHA2 9JQHA5 5HY

Medium likelihood (12)

HA2 6AEHA2 6BTHA2 6DZHA2 6EFHA2 7LAHA2 7SYHA2 9AWHA2 9ERHA2 9HHHA2 9JFHA2 9JGHA4 0RJ

Low likelihood (24)

HA2 6BUHA2 6HFHA2 7LBHA2 7RQHA2 7TAHA2 8SEHA2 8TPHA2 9ANHA2 9APHA2 9ARHA2 9ASHA2 9AZHA2 9BBHA2 9DAHA2 9DBHA2 9DXHA2 9FBHA2 9HAHA2 9HJHA2 9HQHA2 9JNHA2 9LDHA4 0QLHA4 0QN

Very low likelihood (1)

HA2 6ED

Postcode districts

HA2 · 41HA4 · 3HA5 · 1

Sources

FloodRadar summarises public flood data. It is not a flood-risk survey of any property, and it does not replace official GOV.UK flood warnings or the GOV.UK long-term flood risk service.

Flood-risk bands: © Environment Agency copyright and/or database right 2025. All rights reserved. Some features of this map are based on digital spatial data from the Centre for Ecology & Hydrology, © NERC (CEH). © Crown Copyright and Database Rights 2025 OS AC0000807064. This product is produced in part from PAF® and Multiple Residence Data, the copyright in which is owned by Royal Mail Group Limited and/or Royal Mail Group plc. All rights reserved. Licence number AC0000807064.

Recorded Flood Outlines, flood warning areas and warning history © Environment Agency copyright and/or database right 2025. Licensed under the Open Government Licence v3.0.

River levels and rainfall: Environment Agency real-time flood-monitoring data, updated every 15 minutes (Open Government Licence v3.0).

Average rainfall: HadUK-Grid v1.3.2, Met Office. Contains public sector information licensed under the Open Government Licence v3.0.

Place names: Contains OS data © Crown copyright and database rights 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Contains National Statistics data © Crown copyright and database right 2026. Licensed under the Open Government Licence v3.0.

All data sources & licences