Does CM5 flood?

Yes — parts of the CM5 district carry real flood risk: 7 of its 29 at-risk postcodes reach the Environment Agency's High likelihood band. The CM5 postcode district covers Ongar, Theydon Bois with Passingford, close to High Ongar, Moreton, Chipping Ongar, and surrounding villages in Essex.

29 postcodes in the CM5 district appear in the Environment Agency's rivers-and-sea flood-risk dataset — worst bands: 7 high, 6 medium, 16 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 CM5 postcodes are at risk?

CM5 0AU up to High CM5 0DR up to High CM5 0EY up to High CM5 0JQ up to High CM5 0JU up to High CM5 0LJ up to High CM5 0NN up to High CM5 0DE up to Medium CM5 0ET up to Medium CM5 0NW up to Medium CM5 0QF up to Medium CM5 9EE up to Medium CM5 9PE up to Medium CM5 0AT up to Low CM5 0EZ up to Low CM5 0FE up to Low CM5 0FL up to Low CM5 0GA up to Low CM5 0NX up to Low CM5 0PF up to Low CM5 0PG up to Low CM5 0PH up to Low CM5 0PZ up to Low CM5 0RZ up to Low CM5 0SQ up to Low CM5 9DT up to Low CM5 9HH up to Low CM5 9JX up to Low CM5 9RN up to Low

Rivers and flooding history near CM5

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

High Ongar on the River Roding — 2 km away, highest on record 2.18m
Moreton on the Cripsey Brook — 2.8 km away, highest on record 4.06m
Shonks Mill Bridge on the River Roding — 8.5 km away, highest on record 2.39m
Mountnessing on the River Wid — 11.1 km away, highest on record 2.75m

72 official flood warnings and alerts have been raised within ~10 km of the district's centre since 2006, most recently 16 February 2026. Warnings cover flood areas, not individual addresses.

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

January 2018 flooding — about 2 km from the centre
February 2009 flooding — about 2 km from the centre
October 2001 flooding — about 9.2 km from the centre
October 1993 flooding — about 2.9 km from the centre

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

🏠 Buying or renting in CM5? 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

CM4 CM6 CM3 CM7 CM2 CM8 CM1 CM9

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.