Flood risk

How likely is it to flood where you live?

The Environment Agency maps the chance of flooding for every corner of England, and Natural Resources Wales and SEPA do the same for Wales and Scotland. This page reads those maps for one postcode: the risk from rivers and the sea with defences counted, the risk from surface water after heavy rain, the planning flood zone that ignores defences, every flood the Agency has recorded nearby since 1946, and the Floodline areas and live warnings that cover the spot.

  • Rivers & sea risk band
  • Surface water risk
  • Planning flood zone
  • Floods recorded since 1946

How this works

The page asks six of the Environment Agency’s published map layers about one point, rounded to about 100 m. The Risk of Flooding from Rivers and Sea layer gives the modelled chance of flooding in any year with today’s defences in place, in four bands; the three Risk of Flooding from Surface Water extents show where rain that cannot drain away would pool at 1 in 30, 1 in 100 and 1 in 1,000 year rainfall; the Flood Map for Planning zones are what a planning application is judged against, and ignore defences on purpose; the Recorded Flood Outlines are the floods surveyed since 1946, most fully since the 1990s; and the Floodline warning and alert areas say which warnings would name this spot, with the live feed showing any in force now. In Wales the page reads Natural Resources Wales’s rivers-and-sea assessment and in Scotland SEPA’s river, coastal and surface water extents, which is all those agencies publish as open layers; Northern Ireland’s maps are linked when a postcode lands there. The mapped layers are cached for a week per cell, the live warnings for five minutes.

Sources

  • Environment Agency: Risk of Flooding from Rivers and Sea, Risk of Flooding from Surface Water, Flood Map for Planning (Flood Zones), Recorded Flood Outlines, Flood Warning and Flood Alert Areas, and the real-time flood-monitoring API. © Environment Agency copyright and/or database right. Open Government Licence v3.
  • Postcodes: postcodes.io / ONS Postcode Directory (OGL v3).