Residents in a reservoir flood area, every council ranked
Where a large reservoir would flood if it failed. Failure is very rare: this is where the water would go, not how likely it is. Figures for October 2026, published for 296 councils in England. Lowest first: the order says where a council sits, not whether that is good.
Joint lowest: 26 councils, 0%. The council in the middle: Cotswold, 3.5%. Highest: Spelthorne, 97.8%.
| Place | Council | Figure |
|---|---|---|
| 1 joint | AdurSouth East | 0% |
| 1 joint | Basingstoke and DeaneSouth East | 0% |
| 1 joint | BrentwoodEast of England | 0% |
| 1 joint | Brighton and HoveSouth East | 0% |
| 1 joint | ChichesterSouth East | 0% |
| 1 joint | EastbourneSouth East | 0% |
| 1 joint | EastleighSouth East | 0% |
| 1 joint | Epsom and EwellSouth East | 0% |
| 1 joint | FarehamSouth East | 0% |
| 1 joint | GosportSouth East | 0% |
| 1 joint | Great YarmouthEast of England | 0% |
| 1 joint | HarboroughEast Midlands | 0% |
| 1 joint | HarlowEast of England | 0% |
| 1 joint | IpswichEast of England | 0% |
| 1 joint | Isle of WightSouth East | 0% |
| 1 joint | Isles of ScillySouth West | 0% |
| 1 joint | MansfieldEast Midlands | 0% |
| 1 joint | Mid SussexSouth East | 0% |
| 1 joint | Oadby and WigstonEast Midlands | 0% |
| 1 joint | RochfordEast of England | 0% |
| 1 joint | South NorfolkEast of England | 0% |
| 1 joint | Southend-on-SeaEast of England | 0% |
| 1 joint | ThanetSouth East | 0% |
| 1 joint | TorbaySouth West | 0% |
| 1 joint | Welwyn HatfieldEast of England | 0% |
| 1 joint | WorthingSouth East | 0% |
| 27 joint | MedwaySouth East | 0.1% |
| 27 joint | WirralNorth West | 0.1% |
| 29 joint | MiddlesbroughNorth East | 0.2% |
| 29 joint | Newcastle-under-LymeWest Midlands | 0.2% |
| 29 joint | PlymouthSouth West | 0.2% |
| 29 joint | SwaleSouth East | 0.2% |
| 33 joint | BlabyEast Midlands | 0.3% |
| 33 joint | CoventryWest Midlands | 0.3% |
| 33 joint | East HampshireSouth East | 0.3% |
| 33 joint | Hinckley and BosworthEast Midlands | 0.3% |
| 33 joint | North TynesideNorth East | 0.3% |
| 33 joint | SunderlandNorth East | 0.3% |
| 33 joint | SuttonLondon | 0.3% |
| 40 joint | BrecklandEast of England | 0.4% |
| 40 joint | BroadlandEast of England | 0.4% |
| 40 joint | FyldeNorth West | 0.4% |
| 40 joint | StevenageEast of England | 0.4% |
| 40 joint | TandridgeSouth East | 0.4% |
| 40 joint | UttlesfordEast of England | 0.4% |
| 46 joint | East SuffolkEast of England | 0.5% |
| 46 joint | LutonEast of England | 0.5% |
| 46 joint | Test ValleySouth East | 0.5% |
| 46 joint | WinchesterSouth East | 0.5% |
| 50 | North NorthamptonshireEast Midlands | 0.6% |
| 51 joint | AshfieldEast Midlands | 0.7% |
| 51 joint | North HertfordshireEast of England | 0.7% |
| 51 joint | SandwellWest Midlands | 0.7% |
| 51 joint | WatfordEast of England | 0.7% |
| 55 joint | DacorumEast of England | 0.8% |
| 55 joint | HavantSouth East | 0.8% |
| 55 joint | LancasterNorth West | 0.8% |
| 55 joint | MertonLondon | 0.8% |
| 55 joint | New ForestSouth East | 0.8% |
| 55 joint | North NorfolkEast of England | 0.8% |
| 55 joint | South GloucestershireSouth West | 0.8% |
| 62 joint | ArunSouth East | 0.9% |
| 62 joint | Mid SuffolkEast of England | 0.9% |
| 64 joint | HastingsSouth East | 1% |
| 64 joint | HaveringLondon | 1% |
| 64 joint | TendringEast of England | 1% |
| 67 joint | Central BedfordshireEast of England | 1.1% |
| 67 joint | CornwallSouth West | 1.1% |
| 67 joint | DoverSouth East | 1.1% |
| 67 joint | Forest of DeanSouth West | 1.1% |
| 67 joint | HyndburnNorth West | 1.1% |
| 67 joint | Mole ValleySouth East | 1.1% |
| 67 joint | SevenoaksSouth East | 1.1% |
| 67 joint | St AlbansEast of England | 1.1% |
| 67 joint | West OxfordshireSouth East | 1.1% |
| 76 joint | BolsoverEast Midlands | 1.2% |
| 76 joint | Bracknell ForestSouth East | 1.2% |
| 76 joint | BraintreeEast of England | 1.2% |
| 76 joint | GraveshamSouth East | 1.2% |
| 76 joint | WolverhamptonWest Midlands | 1.2% |
| 81 joint | DarlingtonNorth East | 1.3% |
| 81 joint | HorshamSouth East | 1.3% |
| 81 joint | North LincolnshireYorkshire and the Humber | 1.3% |
| 81 joint | South TynesideNorth East | 1.3% |
| 81 joint | WalsallWest Midlands | 1.3% |
| 81 joint | WiltshireSouth West | 1.3% |
| 87 joint | Cheshire EastNorth West | 1.4% |
| 87 joint | DartfordSouth East | 1.4% |
| 87 joint | HaltonNorth West | 1.4% |
| 87 joint | North East DerbyshireEast Midlands | 1.4% |
| 87 joint | Nuneaton and BedworthWest Midlands | 1.4% |
| 87 joint | RotherhamYorkshire and the Humber | 1.4% |
| 93 joint | SeftonNorth West | 1.5% |
| 93 joint | SouthamptonSouth East | 1.5% |
| 95 joint | BaberghEast of England | 1.6% |
| 95 joint | BromleyLondon | 1.6% |
| 95 joint | DorsetSouth West | 1.6% |
| 95 joint | DudleyWest Midlands | 1.6% |
| 95 joint | Newcastle upon TyneNorth East | 1.6% |
| 95 joint | South CambridgeshireEast of England | 1.6% |
| 95 joint | StockportNorth West | 1.6% |
| 102 joint | BasildonEast of England | 1.7% |
| 102 joint | HerefordshireWest Midlands | 1.7% |
| 102 joint | LiverpoolNorth West | 1.7% |
| 105 joint | BarnetLondon | 1.8% |
| 105 joint | CroydonLondon | 1.8% |
| 105 joint | GuildfordSouth East | 1.8% |
| 105 joint | North SomersetSouth West | 1.8% |
| 105 joint | OldhamNorth West | 1.8% |
| 105 joint | PortsmouthSouth East | 1.8% |
| 105 joint | Surrey HeathSouth East | 1.8% |
| 112 joint | BurnleyNorth West | 2% |
| 112 joint | County DurhamNorth East | 2% |
| 112 joint | WealdenSouth East | 2% |
| 115 joint | Bournemouth, Christchurch and PooleSouth West | 2.1% |
| 115 joint | LewesSouth East | 2.1% |
| 115 joint | South HamsSouth West | 2.1% |
| 115 joint | Stoke-on-TrentWest Midlands | 2.1% |
| 115 joint | WaverleySouth East | 2.1% |
| 120 | RedditchWest Midlands | 2.2% |
| 121 joint | TorridgeSouth West | 2.3% |
| 121 joint | WychavonWest Midlands | 2.3% |
| 123 | Telford and WrekinWest Midlands | 2.4% |
| 124 joint | North West LeicestershireEast Midlands | 2.5% |
| 124 joint | Staffordshire MoorlandsWest Midlands | 2.5% |
| 124 joint | Tunbridge WellsSouth East | 2.5% |
| 127 | WiganNorth West | 2.6% |
| 128 joint | Redcar and ClevelandNorth East | 2.7% |
| 128 joint | ShropshireWest Midlands | 2.7% |
| 128 joint | StaffordWest Midlands | 2.7% |
| 128 joint | Stockton-on-TeesNorth East | 2.7% |
| 132 joint | BarnsleyYorkshire and the Humber | 2.8% |
| 132 joint | South OxfordshireSouth East | 2.8% |
| 132 joint | Vale of White HorseSouth East | 2.8% |
| 135 joint | Cheshire West and ChesterNorth West | 2.9% |
| 135 joint | City of LondonLondon | 2.9% |
| 135 joint | StroudSouth West | 2.9% |
| 138 | King's Lynn and West NorfolkEast of England | 3% |
| 139 joint | Castle PointEast of England | 3.1% |
| 139 joint | East DevonSouth West | 3.1% |
| 139 joint | RugbyWest Midlands | 3.1% |
| 142 joint | Amber ValleyEast Midlands | 3.2% |
| 142 joint | BuckinghamshireSouth East | 3.2% |
| 142 joint | HarrowLondon | 3.2% |
| 145 joint | NorthumberlandNorth East | 3.4% |
| 145 joint | SolihullWest Midlands | 3.4% |
| 145 joint | TeignbridgeSouth West | 3.4% |
| 148 joint | CotswoldSouth West | 3.5% |
| 148 joint | LeedsYorkshire and the Humber | 3.5% |
| 148 joint | Milton KeynesSouth East | 3.5% |
| 148 joint | RotherSouth East | 3.5% |
| 152 joint | ChelmsfordEast of England | 3.6% |
| 152 joint | WyreNorth West | 3.6% |
| 154 joint | East CambridgeshireEast of England | 3.7% |
| 154 joint | PendleNorth West | 3.7% |
| 156 | CambridgeEast of England | 3.8% |
| 157 joint | BexleyLondon | 3.9% |
| 157 joint | BromsgroveWest Midlands | 3.9% |
| 157 joint | CanterburySouth East | 3.9% |
| 157 joint | SheffieldYorkshire and the Humber | 3.9% |
| 157 joint | West SuffolkEast of England | 3.9% |
| 162 joint | HertsmereEast of England | 4% |
| 162 joint | South RibbleNorth West | 4% |
| 164 joint | BostonEast Midlands | 4.2% |
| 164 joint | HartSouth East | 4.2% |
| 164 joint | South StaffordshireWest Midlands | 4.2% |
| 164 joint | West NorthamptonshireEast Midlands | 4.2% |
| 168 joint | BradfordYorkshire and the Humber | 4.3% |
| 168 joint | FenlandEast of England | 4.3% |
| 168 joint | WakefieldYorkshire and the Humber | 4.3% |
| 171 joint | ChesterfieldEast Midlands | 4.4% |
| 171 joint | PeterboroughEast of England | 4.4% |
| 171 joint | West DevonSouth West | 4.4% |
| 174 joint | CamdenLondon | 4.5% |
| 174 joint | Mid DevonSouth West | 4.5% |
| 174 joint | SwindonSouth West | 4.5% |
| 174 joint | Three RiversEast of England | 4.5% |
| 178 joint | BoltonNorth West | 4.7% |
| 178 joint | North KestevenEast Midlands | 4.7% |
| 178 joint | WokinghamSouth East | 4.7% |
| 181 joint | MaidstoneSouth East | 4.8% |
| 181 joint | North East LincolnshireYorkshire and the Humber | 4.8% |
| 183 joint | AshfordSouth East | 5% |
| 183 joint | BirminghamWest Midlands | 5% |
| 183 joint | Stratford-on-AvonWest Midlands | 5% |
| 186 joint | Blackburn with DarwenNorth West | 5.1% |
| 186 joint | TamesideNorth West | 5.1% |
| 188 | West LancashireNorth West | 5.2% |
| 189 joint | BlackpoolNorth West | 5.3% |
| 189 joint | Cannock ChaseWest Midlands | 5.3% |
| 189 joint | ChorleyNorth West | 5.3% |
| 189 joint | IslingtonLondon | 5.3% |
| 189 joint | WokingSouth East | 5.3% |
| 189 joint | WorcesterWest Midlands | 5.3% |
| 195 joint | BassetlawEast Midlands | 5.4% |
| 195 joint | Malvern HillsWest Midlands | 5.4% |
| 197 joint | CherwellSouth East | 5.6% |
| 197 joint | KirkleesYorkshire and the Humber | 5.6% |
| 199 joint | EalingLondon | 5.7% |
| 199 joint | PrestonNorth West | 5.7% |
| 199 joint | Reigate and BansteadSouth East | 5.7% |
| 202 | East HertfordshireEast of England | 5.8% |
| 203 | CheltenhamSouth West | 5.9% |
| 204 joint | BrentLondon | 6.1% |
| 204 joint | High PeakEast Midlands | 6.1% |
| 204 joint | North WarwickshireWest Midlands | 6.1% |
| 204 joint | RedbridgeLondon | 6.1% |
| 204 joint | West BerkshireSouth East | 6.1% |
| 209 | ColchesterEast of England | 6.2% |
| 210 joint | East LindseyEast Midlands | 6.5% |
| 210 joint | Wyre ForestWest Midlands | 6.5% |
| 212 joint | Epping ForestEast of England | 6.6% |
| 212 joint | WarwickWest Midlands | 6.6% |
| 214 joint | HartlepoolNorth East | 6.8% |
| 214 joint | HillingdonLondon | 6.8% |
| 216 joint | LichfieldWest Midlands | 7% |
| 216 joint | NorwichEast of England | 7% |
| 216 joint | RutlandEast Midlands | 7% |
| 219 joint | BristolSouth West | 7.3% |
| 219 joint | St. HelensNorth West | 7.3% |
| 221 | North DevonSouth West | 7.5% |
| 222 joint | Bath and North East SomersetSouth West | 7.6% |
| 222 joint | Folkestone and HytheSouth East | 7.6% |
| 224 joint | KnowsleyNorth West | 7.7% |
| 224 joint | SomersetSouth West | 7.7% |
| 226 | TamworthWest Midlands | 7.8% |
| 227 | GedlingEast Midlands | 8.3% |
| 228 | CumberlandNorth West | 8.4% |
| 229 | DerbyEast Midlands | 8.8% |
| 230 joint | CrawleySouth East | 9% |
| 230 joint | Kingston upon HullYorkshire and the Humber | 9% |
| 232 joint | Derbyshire DalesEast Midlands | 9.1% |
| 232 joint | MaldonEast of England | 9.1% |
| 232 joint | RushmoorSouth East | 9.1% |
| 235 | GatesheadNorth East | 9.2% |
| 236 | North YorkshireYorkshire and the Humber | 9.3% |
| 237 joint | Ribble ValleyNorth West | 9.8% |
| 237 joint | Tonbridge and MallingSouth East | 9.8% |
| 239 | LeicesterEast Midlands | 10% |
| 240 | Westmorland and FurnessNorth West | 10.2% |
| 241 | ExeterSouth West | 10.3% |
| 242 joint | NottinghamEast Midlands | 10.4% |
| 242 joint | RochdaleNorth West | 10.4% |
| 244 | CalderdaleYorkshire and the Humber | 10.8% |
| 245 | ThurrockEast of England | 11.4% |
| 246 | Barking and DagenhamLondon | 11.7% |
| 247 | ReadingSouth East | 11.9% |
| 248 | CharnwoodEast Midlands | 12.1% |
| 249 | GreenwichLondon | 12.5% |
| 250 joint | BedfordEast of England | 12.6% |
| 250 joint | HackneyLondon | 12.6% |
| 252 | OxfordSouth East | 12.8% |
| 253 | RossendaleNorth West | 12.9% |
| 254 | BroxbourneEast of England | 13.2% |
| 255 | GloucesterSouth West | 13.4% |
| 256 joint | DoncasterYorkshire and the Humber | 13.7% |
| 256 joint | MeltonEast Midlands | 13.7% |
| 258 | East Riding of YorkshireYorkshire and the Humber | 13.8% |
| 259 | Waltham ForestLondon | 13.9% |
| 260 joint | BuryNorth West | 14.7% |
| 260 joint | West LindseyEast Midlands | 14.7% |
| 262 | South DerbyshireEast Midlands | 14.8% |
| 263 | TewkesburySouth West | 15% |
| 264 | South HollandEast Midlands | 15.2% |
| 265 | Newark and SherwoodEast Midlands | 15.5% |
| 266 | South KestevenEast Midlands | 15.9% |
| 267 joint | Kensington and ChelseaLondon | 18.7% |
| 267 joint | LewishamLondon | 18.7% |
| 267 joint | YorkYorkshire and the Humber | 18.7% |
| 270 | TraffordNorth West | 18.8% |
| 271 | BroxtoweEast Midlands | 19.2% |
| 272 | Windsor and MaidenheadSouth East | 20.1% |
| 273 | RushcliffeEast Midlands | 20.2% |
| 274 | HaringeyLondon | 20.8% |
| 275 | SalfordNorth West | 21.2% |
| 276 | Kingston upon ThamesLondon | 21.3% |
| 277 | LincolnEast Midlands | 21.6% |
| 278 | SloughSouth East | 21.8% |
| 279 | EnfieldLondon | 22.2% |
| 280 | HounslowLondon | 22.8% |
| 281 | WestminsterLondon | 23% |
| 282 | LambethLondon | 23.4% |
| 283 | ManchesterNorth West | 24.7% |
| 284 | HuntingdonshireEast of England | 25% |
| 285 | WarringtonNorth West | 26.6% |
| 286 | WandsworthLondon | 27.9% |
| 287 | Tower HamletsLondon | 28.8% |
| 288 | East StaffordshireWest Midlands | 29.7% |
| 289 | ErewashEast Midlands | 29.8% |
| 290 | RunnymedeSouth East | 42.1% |
| 291 | ElmbridgeSouth East | 44.3% |
| 292 | NewhamLondon | 45.6% |
| 293 | Richmond upon ThamesLondon | 54.5% |
| 294 | SouthwarkLondon | 74.2% |
| 295 | Hammersmith and FulhamLondon | 88.9% |
| 296 | SpelthorneSouth East | 97.8% |
Not in this list
- Northern Ireland. Only the Environment Agency, for England, publishes outlines of where a reservoir would flood.
- Scotland. Only the Environment Agency, for England, publishes outlines of where a reservoir would flood.
- Wales. Only the Environment Agency, for England, publishes outlines of where a reservoir would flood.
Environment Agency, Reservoir Flood Extents, dry day and wet day, 2026-10-20, read at every census area · October 2026 · fetched 22 October 2026 · How this is measured
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