Does CM12 flood?

Yes — parts of the CM12 district carry real flood risk: 6 of its 17 at-risk postcodes reach the Environment Agency's High likelihood band. The CM12 postcode district covers Burstead, close to Billericay, Great Burstead, Mountnessing, and surrounding villages in parts of Essex and Greater London.

17 postcodes in the CM12 district appear in the Environment Agency's rivers-and-sea flood-risk dataset — worst bands: 6 high, 2 medium, 9 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 CM12 postcodes are at risk?

CM12 0ER up to High CM12 0LE up to High CM12 0LG up to High CM12 0LN up to High CM12 0LW up to High CM12 9TT up to High CM12 9HS up to Medium CM12 9TZ up to Medium CM12 0GG up to Low CM12 0TN up to Low CM12 0TS up to Low CM12 9HT up to Low CM12 9UA up to Low CM12 9UN up to Low CM12 9UP up to Low CM12 9UR up to Low CM12 9UX up to Low

Rivers and flooding history near CM12

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

Wardropers on the River Wid — 3 km away, highest on record 2.34m
Noak Bridge on the River Crouch — 3.1 km away, highest on record 1.14m
Mountnessing on the River Wid — 5.4 km away, highest on record 2.75m
Wickford on the River Crouch — 8 km away, highest on record 2.69m

216 official flood warnings and alerts have been raised within ~10 km of the district's centre since 2006 (46 at warning level or above), most recently 19 February 2026. Warnings cover flood areas, not individual addresses.

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

1968 September Flood Outline (1968) — about 54.6 km from the centre
1958 Flood Outline (1958) — about 13.1 km from the centre
1953 Coast Flood Outline Essex (1953) — about 31.5 km from the centre

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

🏠 Buying or renting in CM12? 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

CM11 CM13 CM14 CM15 CM9 CM16 CM8 CM17

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.