Does CM11 flood?

Yes — parts of the CM11 district carry real flood risk: 5 of its 14 at-risk postcodes reach the Environment Agency's High likelihood band. The CM11 postcode district covers Castledon & Crouch, South Hanningfield, Stock and Margaretting, close to Great Burstead, Wickford, Billericay, and surrounding villages in Essex.

14 postcodes in the CM11 district appear in the Environment Agency's rivers-and-sea flood-risk dataset — worst bands: 5 high, 1 medium, 6 low, 2 very low. A postcode not listed here has no properties in any recorded risk band (which is good news, but never proof it cannot flood).

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Which CM11 postcodes are at risk?

CM11 2HQ up to High CM11 2JF up to High CM11 2JR up to High CM11 2UH up to High CM11 2UN up to High CM11 2JS up to Medium CM11 2ET up to Low CM11 2FA up to Low CM11 2FD up to Low CM11 2TX up to Low CM11 2UJ up to Low CM11 2YG up to Low CM11 2FB up to Very low CM11 2UF up to Very low

Rivers and flooding history near CM11

The rivers that matter here, each monitored live on FloodRadar:

Noak Bridge on the River Crouch — 2.5 km away, highest on record 1.14m
Wickford on the River Crouch — 4.7 km away, highest on record 2.69m
Wardropers on the River Wid — 5.7 km away, highest on record 2.34m
Mountnessing on the River Wid — 8.7 km away, highest on record 2.75m

49 official flood warnings and alerts have been raised within ~10 km of the district's centre since 2006 (13 at warning level or above), most recently 5 January 2025. Warnings cover flood areas, not individual addresses.

Recorded flood extents near the district (Environment Agency record):

1968 September Flood Outline (1968) — about 54.4 km from the centre
1958 Flood Outline (1958) — about 11.4 km from the centre
1953 Coast Flood Outline Essex (1953) — about 28.8 km from the centre

Records, not floods: no outline on the record is not evidence a place has not flooded.

🏠 Buying or renting in CM11? The full property flood-risk report covers any postcode here — the official likelihood band, every recorded flood nearby with distances, warning history year by year, how the local rivers behave, and an insurance outlook, print-ready for £19. See what's in the report →

Flood risk in nearby postcode districts

CM12 CM13 CM9 CM14 CM8 CM15 CM7 CM16

Band = the worst likelihood band of any property in that postcode (EA Risk of Flooding from Rivers & Sea, defence-adjusted, area-level). Check any postcode in detail — or get the full £19 property report — at the property flood-risk report. © 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.