Horsham Flood Risk
In Horsham, 564 of 84,597 properties (0.7%) 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 224th of 296 local authorities in England by number.
By bandProperties in Horsham 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 | 240 | 140 |
| Medium | between 1% and 3.3% (1 in 100 to 1 in 30) chance in any year | 324 | 238 |
| Low | between 0.1% and 1% (1 in 1,000 to 1 in 100) chance in any year | 590 | 437 |
| Very low | less than 0.1% (1 in 1,000) chance in any year | 14 | 6 |
378 of the high- or medium-risk properties are homes and 91 are non-residential. 127 postcodes in Horsham have at least one property at high or medium risk.
Postcode districtsFlood risk across Horsham
Counts are for the part of each district inside Horsham.
Recorded floodsPast floods mapped in Horsham
The Environment Agency has mapped flood outlines on 19 dates in postcode districts that mostly lie in Horsham since 1960; the most recent started on 1 Dec 2013.
1960s 3 1970s 10 1980s 5 2010s 1
| Started | Place / name in the record | Source of flooding | Cause | Districts |
|---|---|---|---|---|
| 1 Dec 2013 – 1 Feb 2014 | Arun Valley | Main river | Overtopping of defences | RH20 |
| 9 Dec 1982 | BILLINGSHURST 2 outlines | Drainage | Local drainage/surface water | RH14 |
| 6 Aug 1981 | STORRINGTON 2 outlines | Main river, other | Channel capacity exceeded (no raised defences) | RH14 RH20 |
| 2 Jun 1981 | STORRINGTON 5 outlines | Drainage, main river | Other | RH12 RH14 RH20 |
| 1 Jun 1981 | BILLINGSHURST 7 outlines | Main river, drainage | Other | BN44 BN5 RH12 RH14 RH20 |
| 11 Oct 1980 | STEYNING 2 outlines | Main river | Channel capacity exceeded (no raised defences) | BN44 |
| 28 Dec 1979 | Wisborough Green | Not recorded | Channel capacity exceeded (no raised defences) | RH14 |
| 9 Apr 1979 | AMBERLEY | Main river | Overtopping of defences | RH20 |
| 29 Nov 1976 | BILLINGSHURST | Main river | Channel capacity exceeded (no raised defences) | RH14 |
| 24 Oct 1975 | AMBERLEY | Main river | Overtopping of defences | RH20 |
| 7 Aug 1975 | Upper Beeding | Not recorded | Not recorded | BN5 |
| 23 Nov 1974 | STEYNING 14 outlines | Main river, drainage | Channel capacity exceeded (no raised defences) | BN44 BN5 RH13 RH14 RH20 |
| 11 Feb 1974 | PULBOROUGH 6 outlines | Main river, other | Overtopping of defences | BN5 RH13 RH20 |
| 24 Jan 1974 | AMBERLEY | Main river | Overtopping of defences | RH20 |
| 26 Jan 1971 | COLDWALTHAM | Main river | Other | RH20 |
| 12 Jan 1970 | AMBERLEY | Other | Overtopping of defences | RH20 |
| 16 Sep 1968 | BILLINGSHURST | Drainage | Overtopping of defences | RH14 |
| 15 Sep 1968 | PULBOROUGH 4 outlines | Main river | Channel capacity exceeded (no raised defences) | RH12 RH14 RH20 |
| 1 Nov 1960 | SHIPLEY 2 outlines | Other | Not recorded | RH13 |
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.
"Horsham" means the local authority area (ONS code E07000227), not only the town centre.
If you live in Horsham
- 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 Horsham at risk of flooding?
In Horsham, 564 of 84,597 properties (0.7%) 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 224th of 296 local authorities in England by number.
Which parts of Horsham have the most properties at flood risk?
Postcode district BN44 has the most: 252 properties at high or medium risk (4.4% of its properties in Horsham). The table on this page lists every district.
When did Horsham last flood?
The Environment Agency has mapped flood outlines on 19 dates in postcode districts that mostly lie in Horsham since 1960; the most recent started on 1 Dec 2013.
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.