SN15 Flood Risk
In postcode district SN15 (Wiltshire), 270 of 22,600 properties (1.2%) 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 is the 612th highest count of 2,181 districts in England.
By bandProperties in SN15 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 | 114 | 37 |
| Medium | between 1% and 3.3% (1 in 100 to 1 in 30) chance in any year | 156 | 90 |
| Low | between 0.1% and 1% (1 in 1,000 to 1 in 100) chance in any year | 376 | 216 |
| Very low | less than 0.1% (1 in 1,000) chance in any year | 3 | 3 |
127 of the high- or medium-risk properties are homes and 71 are non-residential (shops, offices, farms, public buildings); the rest are unclassified. By share, SN15 ranks 901st of 2,084 districts with at least 500 properties.
Postcode sectorsWhere in SN15 the risk sits
| Sector | Properties | High | Medium | Low | Very low | High + medium share |
|---|---|---|---|---|---|---|
| SN15 0 | 1 | 0 | 0 | 0 | 0 | 0.0% |
| SN15 1 | 4,244 | 0 | 7 | 61 | 0 | 0.2% |
| SN15 2 | 3,936 | 12 | 18 | 12 | 0 | 0.8% |
| SN15 3 | 6,276 | 23 | 92 | 218 | 3 | 1.8% |
| SN15 4 | 5,099 | 67 | 35 | 72 | 0 | 2.0% |
| SN15 5 | 3,044 | 12 | 4 | 13 | 0 | 0.5% |
Recorded floodsPast floods mapped near SN15
The Environment Agency has mapped flood outlines on 36 dates near SN15 since 1894; the most recent started on 21 Oct 2023.
| Started | Place / name in the record | Source of flooding | Cause |
|---|---|---|---|
| 21 Oct 2023 | This represents flooding on the at Dauntsey in | Main river | Channel capacity exceeded (no raised defences) |
| 7 Jan 2014 | This represents flooding in the area in 3 outlines | Ordinary watercourse, drainage | Groundwater/high water table |
| 4 Jan 2014 | This represents flooding in the area in | Drainage | Not recorded |
| 2 Jan 2014 | This represents flooding in the area in | Not recorded | Not recorded |
| 24 Dec 2013 | Dauntsey to 2 outlines | Ordinary watercourse, main river | Channel capacity exceeded (no raised defences) |
| 21 Nov 2012 | Chippenham 4 outlines | Main river, ordinary watercourse | Channel capacity exceeded (no raised defences) |
| 10 Feb 2009 | North Wessex 4 outlines | Main river | Channel capacity exceeded (no raised defences) |
| 16 Mar 2008 – 17 Mar 2008 | SurfaceWater Dauntsey 2 outlines | Drainage, ordinary watercourse | Obstruction/blockage - culvert |
| 15 Jul 2007 | This represents flooding in this area in | Main river | Not recorded |
| 30 Oct 2000 – 1 Nov 2000 | This represents flooding in the area in 4 outlines | Main river | Other |
| 30 Oct 1999 | This represents flooding in the area in | Main river | Other |
| 19 Jan 1999 – 22 Jan 1999 | Avon Langley Burrell Chippenham 6 outlines | Main river, drainage | Channel capacity exceeded (no raised defences) |
| 9 May 1996 | This represents flooding in the area in 2 outlines | Drainage | Local drainage/surface water |
| 18 Mar 1996 | This represents flooding in this area in 5 outlines | Drainage, ordinary watercourse | Local drainage/surface water |
| 6 Nov 1995 | This represents flooding in the area in | Not recorded | Not recorded |
| 1 Feb 1990 | This represents flooding in the area in 4 outlines | Ordinary watercourse, other | Obstruction/blockage - channel |
| 23 Dec 1985 – 26 Dec 1985 | This represents flooding in the area in 4 outlines | Ordinary watercourse, main river | Other |
| 7 Mar 1981 – 12 Mar 1981 | This represents flooding in the area in | Main river | Other |
| 4 Aug 1980 | This represents flooding in the area in | Main river | Obstruction/blockage - culvert |
| 27 Dec 1979 – 28 Dec 1979 | Avon Chippenham 3 outlines | Main river | Channel capacity exceeded (no raised defences) |
| 6 Mar 1978 | This represents flooding in the area in 37 outlines | Drainage, ordinary watercourse | Local drainage/surface water |
| 1 Nov 1976 | This represents flooding in the area in | Main river | Channel capacity exceeded (no raised defences) |
| 9 Feb 1974 – 10 Feb 1974 | Ladyfield Brook Chippenham | Main river | Channel capacity exceeded (no raised defences) |
| 11 Jun 1971 | This represents flooding in the area in 2 outlines | Main river | Other |
| 11 Feb 1971 | This represents flooding in this area in | Ordinary watercourse | Other |
| 10 Jul 1968 | This represents flooding in the area in 13 outlines | Main river, other | Channel capacity exceeded (no raised defences) |
| 21 Feb 1967 – 22 Feb 1967 | LadyfieldBr Chippenham | Main river | Channel capacity exceeded (no raised defences) |
| 18 Nov 1963 – 20 Nov 1963 | This represents flooding in the area in 3 outlines | Main river | Channel capacity exceeded (no raised defences) |
| 5 Dec 1960 | This represents flooding in the area in | Main river | Other |
| 4 Dec 1960 – 5 Dec 1960 | This represents flooding in the area in 16 outlines | Main river | Channel capacity exceeded (no raised defences) |
Showing the 30 most recent of 36 dates.
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.
Local authorities in SN15
- Wiltshire — 22,599 properties, 270 at high or medium risk
Parishes in SN15: Bremhill, Brinkworth, Bromham, Chippenham, Christian Malford, Dauntsey, Derry Hill & Studley, Great Somerford, Heddington, Kington Langley, Lacock, Langley Burrell Without, Lea and Cleverton, Little Somerford, Lydiard Millicent, Lyneham and Bradenstoke, Melksham Without, Seagry, Sutton Benger, Tockenham.
If you live in SN15
- Check your own address on gov.uk; it also covers surface water.
- Sign up for free flood warnings by phone, text or email: gov.uk/get-flood-warnings.
- See what is in force now on flood warnings UK, and river levels. Floodline: 0345 988 1188.
- Never walk or drive through flood water: why shallow water kills.
Nearby districts
FAQQuestions people ask
Is SN15 at risk of flooding?
In postcode district SN15 (Wiltshire), 270 of 22,600 properties (1.2%) 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 is the 612th highest count of 2,181 districts in England.
How many homes in SN15 are at high risk of flooding?
37 homes (residential properties) in SN15 are in areas at high risk (3.3% or greater chance each year) and 90 at medium risk, out of 17,351 homes, per Environment Agency data updated 6 July 2026. This counts rivers and the sea only, not surface water.
Has SN15 flooded before?
The Environment Agency has mapped flood outlines on 36 dates near SN15 since 1894; the most recent started on 21 Oct 2023.
How do I check the flood risk for my own address in SN15?
Use the government's long-term flood risk checker (check-long-term-flood-risk.service.gov.uk): it shows rivers and the sea, surface water, reservoirs and groundwater for one address. District figures here are totals and cannot tell you about a single home.
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.