Slough Flood Risk
In Slough, 1,878 of 62,974 properties (3.0%) are in areas at high or medium risk of flooding from rivers and the sea — at least a 1 in 100 chance in any year — per Environment Agency data updated 6 July 2026; that ranks 108th of 296 local authorities in England by number.
By bandProperties in Slough by flood-risk band
| Risk band | Chance of flooding each year | All properties | Homes |
|---|---|---|---|
| High | 3.3% (1 in 30) or greater chance in any year | 1,379 | 1,250 |
| Medium | between 1% and 3.3% (1 in 100 to 1 in 30) chance in any year | 499 | 480 |
| Low | between 0.1% and 1% (1 in 1,000 to 1 in 100) chance in any year | 2,106 | 1,936 |
| Very low | less than 0.1% (1 in 1,000) chance in any year | 1,941 | 1,704 |
1,730 of the high- or medium-risk properties are homes and 127 are non-residential. 224 postcodes in Slough have at least one property at high or medium risk.
Postcode districtsFlood risk across Slough
Counts are for the part of each district inside Slough.
Recorded floodsPast floods mapped in Slough
The Environment Agency has mapped flood outlines on 8 dates in postcode districts that mostly lie in Slough since 1947; the most recent started on 30 Jan 2021.
1940s 1 1970s 1 1990s 1 2000s 2 2010s 2 2020s 1
| Started | Place / name in the record | Source of flooding | Cause | Districts |
|---|---|---|---|---|
| 30 Jan 2021 – 6 Feb 2021 | — 8 outlines | Main river | Channel capacity exceeded (no raised defences) | SL3 |
| 20 Dec 2019 – 23 Dec 2019 | — | Main river | Channel capacity exceeded (no raised defences) | SL3 |
| 31 Jan 2014 – 18 Feb 2014 | — 8 outlines | Main river | Channel capacity exceeded (no raised defences) | SL3 |
| 23 Dec 2002 – 12 Jan 2003 | — 149 outlines | Sewer, main river | Channel capacity exceeded (no raised defences) | SL1 SL3 |
| 1 Jan 2000 – 12 Dec 2000 | — 64 outlines | Main river, other | Channel capacity exceeded (no raised defences) | SL1 SL3 |
| 1 Jan 1990 – 12 Dec 1990 | — 3 outlines | Main river | Channel capacity exceeded (no raised defences) | SL3 |
| 1 Jan 1974 – 12 Dec 1974 | — 12 outlines | Main river, other | Channel capacity exceeded (no raised defences) | SL1 SL3 |
| 1 Jan 1947 – 12 Dec 1947 | — 3 outlines | Main river | Channel capacity exceeded (no raised defences) | SL3 |
What this page shows, and what it misses
The Environment Agency's count of properties in each postcode that sit in areas of land at very low, low, medium or high risk of flooding from rivers and the sea, allowing for flood defences and their condition, added up here by postcode district and local authority. Every property in England is counted once, so the share is of all properties in the area.
It misses: surface water (heavy rain), groundwater, sewer and reservoir flooding; Wales, Scotland and Northern Ireland; and anything about a single building. A band describes the land a property stands on, not its floor level or flood protection, so it is not a forecast for any one home. Past floods come from the EA's Recorded Flood Outlines and are placed in the postcode district whose centre is nearest (within 12 km), so a flood near a boundary can be listed under a neighbour. Older records are patchy, and a flood with no outline is not listed.
"Slough" means the local authority area (ONS code E06000039), not only the town centre.
If you live in Slough
- Check your own address on gov.uk; it also covers surface water.
- Sign up for free flood warnings: gov.uk/get-flood-warnings. Floodline: 0345 988 1188.
- What is in force now: flood warnings UK · river levels.
- Never walk or drive through flood water: why shallow water kills.
FAQQuestions people ask
Is Slough at risk of flooding?
In Slough, 1,878 of 62,974 properties (3.0%) are in areas at high or medium risk of flooding from rivers and the sea — at least a 1 in 100 chance in any year — per Environment Agency data updated 6 July 2026; that ranks 108th of 296 local authorities in England by number.
Which parts of Slough have the most properties at flood risk?
Postcode district SL1 has the most: 1,152 properties at high or medium risk (3.9% of its properties in Slough). The table on this page lists every district.
When did Slough last flood?
The Environment Agency has mapped flood outlines on 8 dates in postcode districts that mostly lie in Slough since 1947; the most recent started on 30 Jan 2021.
Does this include surface water flooding?
No. These counts cover flooding from rivers and the sea only. Surface water (heavy rain) flooding affects more properties in England; check it for one address on gov.uk's long-term flood risk service.
Flood risk counts: Environment Agency, Risk of Flooding from Rivers and Sea – Postcodes in Areas at Risk and Recorded Flood Outlines, used under the Open Government Licence v3.0. © Environment Agency copyright and/or database right 2025. All rights reserved. Some features of this information 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.
Local authority of each postcode: Office for National Statistics postcode lookup (May 2026), licensed under the Open Government Licence v3.0. Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. District centres and place names: postcodes.io (ONS/OS open data). Totals, ranks and grouping are Global Incident Tracker's own calculations; the Environment Agency does not endorse them.