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Chelston, Somerset
Up to High likelihood
Properties in TA21 9HP sit in the Environment Agency's High flood-likelihood band (worst property). The band is the worst found in the postcode — it describes the land around properties (defence-adjusted, rivers & sea), not any single address, and not today's conditions.
| Likelihood band | Annual chance | Properties | Of which homes |
|---|---|---|---|
| High | greater than 3.3% | 1 | 0 |
| Medium | 1% – 3.3% | 0 | 0 |
| Low | 0.1% – 1% | 0 | 0 |
| Very low | below 0.1% | 0 | 0 |
Over a 25-year mortgage, a property in a high-likelihood area has at least a 57% chance of flooding at least once.
TA21 9HP gets about 867 mm of rain a year on average (wettest month December, 101 mm; driest May, 52 mm). That is 25% drier than the UK as a whole, which averages 1,163 mm a year.
A thirty-year average for the surrounding area, not a measurement at this address and not a flood risk on its own: a dry area floods when a storm sits over it, and a wet one may drain away perfectly well. Source: Met Office HadUK-Grid 1991–2020 (5 km grid), 2.6 km away. Average rainfall: HadUK-Grid v1.3.2, Met Office. Contains public sector information licensed under the Open Government Licence v3.0.
The ground here sits at about 62 m above sea level and falls 23 m across the surrounding 800 m. Surface water reaching this point runs off ground lying to the south, 3.1 m higher.
The nearest watercourse on the river map is an unnamed stream, about 280 m from the centre of TA21 9HP. It flows into Haywards Water about 2.4 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 an unnamed stream nearest the centre of TA21 9HP. 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.
Because properties in the high likelihood band; 117 official warnings since 2006.
The map above shows the real EA rivers & sea likelihood cells around TA21 9HP. The small panels are illustrative previews of the report's per-layer map views — the full report draws each layer for real, plus recorded extents, defences and a building picker on an interactive map.
Warnings cover flood areas, not individual addresses.
None mapped within ~1 km of this postcode's centre.
No recorded outline near this postcode means no flood was mapped here, which is not evidence none happened: the Environment Agency mapped only some floods, mapping effort rose sharply after about 2000, and surface-water flooding is largely absent from this record. The full report tests every other flood source at the exact building.
2013-14 UK winter floods (2013, 14 warnings nearby) ▶ replay it here · Imogen (2016, 3 warnings nearby) ▶ replay it here · Angus (2016, 2 warnings nearby) ▶ replay it here · Bram (2025, 1 warnings nearby) ▶ replay it here
| Gauge | River | Distance | Typical high | Highest on record |
|---|---|---|---|---|
| Bishops Hull | River Tone | 6.5 km | 0.90 m | 2.59 m |
| Halsewater | Halse Water | 6.7 km | 1.40 m | 2.48 m |
| Milverton | Hillfarrance Brook | 7.2 km | 0.70 m | 1.48 m |
| Greenham | River Tone | 7.6 km | 1.30 m | 2.20 m |
Live levels, predictions and rain-response behaviour are on each gauge's page and in the property report.
| Overflow | Discharges into | Distance | Spills | Hours |
|---|---|---|---|---|
| Mitchels Pool Pumping Station | Haywards Water | 0.9 km | 30 (2024) | 178 |
| Hockholler Pumping Station | Tributary Of River Tone | 1.2 km | 102 (2024) | 338 |
| West Buckland Pumping Station | Trib Of River Tone (s) | 2.5 km | 18 (2024) | 143 |
| The Basins Sewer Cso | Back Stream Via Sws | 2.5 km | 0 (2024) | 0 |
Official annual EDM figures — a water-quality signal for local watercourses, not a property flood-risk factor.
No mapped flood-defence assets within 500 m of the postcode centre. Defences reduce risk, never remove it.
The interactive flood-risk map with a building picker (your exact house, not the postcode), the 2050s climate view, surface-water and planning flood zones at your building, exact recorded-flood distances, year-by-year warning charts, watercourses including culverted streams, an insurance outlook with the Flood Re rules, and a printable document with every dataset receipt — start with the free preview, unlock for £19.
At-risk postcodes near TA21 9HP — all in the TA21 district.
© 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. Recorded Flood Outlines and warning history © Environment Agency copyright and/or database right 2025. Storm-overflow figures: EA Event Duration Monitoring (England); live overflow status © the water companies, incl. Dŵr Cymru Welsh Water and Scottish Water. Flood defences © Environment Agency (OGL v3). This page summarises public area-level data — it is not a flood-risk survey and not a substitute for the official GOV.UK service. All data sources & licences. More postcodes: the TA21 district.