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Does Walthamstow flood? 120 postcodes in Walthamstow are in the Environment Agency's rivers-and-sea flood-risk data (42 High, 23 Medium likelihood) — the breakdown is further down this page.
Conditions are worth watching: the Environment Agency has a Flood Alert in force for Tidal Thames riverside from the Thames Barrier to Putney Bridge — flooding is possible from 01:00 AM to 03:00 AM on Saturday 10th October. Flooding is possible — be prepared and keep an eye on updates.
Updated 2026-10-09 22:01:28 UTC · Official GOV.UK warnings · Flood preparation & help guide
Walthamstow is a town within the London Borough of Waltham Forest in East London. The town borders Chingford to the north, Snaresbrook and South Woodford to the east, Leyton and Leytonstone to the south, and Tottenham to the west. At the 2011 census, Walthamstow had a population of approximately 109,424 and is around 7.5 miles (12 km) north-east of Central London.
Ordnance Survey places 120 postcodes in Walthamstow 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 3,258 properties in the EA dataset's likelihood bands.
| EA likelihood band | Postcodes (worst band) | Properties in the EA dataset | of which homes |
|---|---|---|---|
| High | 42 | 524 | 467 |
| Medium | 23 | 1,113 | 649 |
| Low | 44 | 1,127 | 962 |
| Very low | 11 | 494 | 481 |
| All bands | 120 | 3,258 | 2,559 |
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 20 more at-risk postcodes, listed on the district pages below.
Leyton · Woodford · Hackney · West Ham · Ilford · Hallsville Quarter · East Ham · City of London
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 river map has no watercourse within 1 km of the middle of Walthamstow's gauges.
That means this spot is not on the river map, not that there is no water here: Ordnance Survey’s river map (OS Open Rivers) leaves out small streams, ditches and culverts. Contains OS data © Crown copyright and database rights 2026.
Walthamstow is monitored by 2 Environment Agency river level stations on the Ching Brook, the River Lee, in Greater London. Water levels are updated every 15 minutes, providing real-time flood monitoring for the area.
The Ching Brook is monitored by 1 station (Walthamstow). The River Lee is monitored by 1 station (Walthamstow, Low Hall). Each station records water levels continuously, with data synced to FloodRadar every 5 minutes.
There are 8 Environment Agency flood warning areas within 10km of Walthamstow. When the EA issues a flood warning for any of these areas, it will appear on this page. These include: The Ching Brook in the London Borough of Waltham Forest, including Highams Park; The Pymmes Brook at Upper Edmonton and Tottenham; The Lower River Lee at Hackney and Walthamstow including Lea Bridge, Hackney Marsh and Hackney Wick; The Salmons Brook at Grange Park and Lower Edmonton including World's End.
There are 23 storm overflows within 5km of Walthamstow. None of the 21 with a reporting monitor are currently discharging (2 have no live status right now). 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 Walthamstow, 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.
Walthamstow gets about 609 mm of rain a year on average (wettest month October, 66 mm; driest March, 35 mm). That is 48% 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), 2.4 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 Tidal Thames riverside from the Thames Barrier to Putney Bridge — flooding is possible from 01:00 AM to 03:00 AM on Saturday 10th October. Flooding is possible — be prepared and keep an eye on updates.
Walthamstow has river level monitoring on Ching Brook, River Lee — 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 2 recorded flood extents around the town centre since 1703, most recently in 1947. 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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