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Does Chelmsford flood? 206 postcodes in Chelmsford are in the Environment Agency's rivers-and-sea flood-risk data (32 High, 97 Medium likelihood) — the breakdown is further down this page.
Conditions are worth watching: the Environment Agency has a Flood Alert in force for The Essex coast from Clacton to and including, St Peters Flat and the Colne and Blackwater estuaries — flooding is possible on consecutive tides from 11pm on Friday 9th October through to 1am on Saturday 10th October. Flooding is possible — be prepared and keep an eye on updates.
Updated 2026-10-09 22:01:42 UTC · Official GOV.UK warnings · Flood preparation & help guide
Chelmsford is a city in Essex, England. It is the county town of Essex and one of three cities in the county, along with Colchester and Southend-on-Sea. It is located 31 miles (50 km) north-east of Charing Cross in London, and 22 miles (35 km) south-west of Colchester. At the 2021 census the built up area had a population of 110,625. It gives its name to the wider Chelmsford local government district which also covers an extensive surrounding area.
Ordnance Survey places 206 postcodes in Chelmsford 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 3,503 properties in the EA dataset's likelihood bands.
| EA likelihood band | Postcodes (worst band) | Properties in the EA dataset | of which homes |
|---|---|---|---|
| High | 32 | 139 | 92 |
| Medium | 97 | 1,603 | 1,203 |
| Low | 71 | 1,641 | 1,218 |
| Very low | 6 | 120 | 104 |
| All bands | 206 | 3,503 | 2,617 |
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.
…and 106 more at-risk postcodes, listed on the district pages below.
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.
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.
The nearest watercourse on the river map is the River Can, about 480 m from the middle of Chelmsford's gauges. It flows into the River Chelmer about 2.0 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 the River Can nearest the middle of Chelmsford's gauges. 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.
Chelmsford is monitored by 2 Environment Agency river level stations on the River Can, the River Chelmer, in Essex. Water levels are updated every 15 minutes, providing real-time flood monitoring for the area.
The River Can is monitored by 1 station (Beach's Mill). The River Chelmer is monitored by 1 station (Springfield). Each station records water levels continuously, with data synced to FloodRadar every 5 minutes.
There are 7 Environment Agency flood warning areas within 10km of Chelmsford. When the EA issues a flood warning for any of these areas, it will appear on this page. These include: Riverside properties in Chelmsford, from Rivermead Industrial Estate through Central and Admirals Park including the cricket ground, to Lordship Lane; The Rivers Can and Chelmer through Chelmsford, including the High Street and Meadows Shopping Centre; The River Wid from Ingatestone to Writtle, including Margaretting; The River Wid from Brentwood, to and including Writtle, and the River Can at Chelmsford.
There are 12 storm overflows within 5km of Chelmsford. None of the 12 with a reporting monitor are currently discharging. Enable "Sewage" on the map above to see their locations.
6 of them, nearest first, with their own page of live status and past discharges:
If flooding is forecast in Chelmsford, call Floodline on 0345 988 1188 for the latest information. Move valuables upstairs, turn off gas and electricity if safe to do so, and avoid walking or driving through flood water. Sign up for flood warnings on any station page above to receive email alerts when water levels rise. For emergency numbers, a preparation checklist and insurance guidance, see our flood help & preparation guide.
Chelmsford gets about 563 mm of rain a year on average (wettest month October, 61 mm; driest March, 34 mm). That is 52% drier than the UK as a whole, which averages 1,163 mm a year. See the rain gauges →
A thirty-year average for the area, not a forecast and not a flood risk on its own. Source: Met Office HadUK-Grid 1991–2020 (5 km grid), 2.5 km away. Average rainfall: HadUK-Grid v1.3.2, Met Office. Contains public sector information licensed under the Open Government Licence v3.0.
Floods whose mapped extent (EA Recorded Flood Outlines) reached within ~5 km of the town centre — most recent first. These are records of mapped extents, not a full list of floods. See them on the map →
Records, not floods: no outline on the record is not evidence a place has not flooded.
Current verdict: Watch. Conditions are worth watching: the Environment Agency has a Flood Alert in force for The Essex coast from Clacton to and including, St Peters Flat and the Colne and Blackwater estuaries — flooding is possible on consecutive tides from 11pm on Friday 9th October through to 1am on Saturday 10th October. Flooding is possible — be prepared and keep an eye on updates.
Chelmsford has river level monitoring on River Can, River Chelmer — 2 monitoring stations in total.
Use the GOV.UK Check for Flooding service (check-for-flooding.service.gov.uk) or call Floodline on 0345 988 1188 (24 hours). You can also set up free FloodRadar email or browser alerts from any station page above.
Follow official advice: move valuables and vehicles to safety, never walk or drive through flood water, turn off gas and electricity if safe, and check on vulnerable neighbours. See our flood preparation guide at floodradar.co.uk/flood-help.
Yes — the Environment Agency's Recorded Flood Outlines dataset shows 5 recorded flood extents around the town centre since 1703, most recently in 2009. That is a count of mapped extents, not of separate floods. Records, not floods: no outline on the record is not evidence a place has not flooded. See the flood history link below.
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