This map shows the largest area that might be flooded if a reservoir were to fail and release the water it holds. Since this is a worst case scenario, it's unlikely that any actual flood would be this large.
Click within a green shaded area to find details of the reservoirs that could cause flooding in that area, and the local authority.
The reservoir flood map displays information for large reservoirs holding over 25,000 cubic meters of water. It does not display information for smaller reservoirs or for reservoirs commissioned after reservoir mapping began in spring 2009. The map also does not display information about how likely any area is to be flooded or about the depth or speed of the flood waters.
We are continually reviewing and updating our maps to ensure they are based on the best information we have available. In December, we will publish new and updated flood maps on our website. The maps will show risk of flooding from rivers and the sea, reservoirs and for the first time, surface water. Please check back in December to see the new and updated maps.
How safe are reservoirs?
Reservoir flooding is extremely unlikely to happen. There has been no loss of life in the UK from reservoir flooding since 1925.
All large reservoirs must be inspected and supervised by reservoir panel engineers. As the enforcement authority for the Reservoirs Act 1975 in England, we ensure that reservoirs are inspected regularly and essential safety work is carried out.
However, in the unlikely event that a reservoir dam failed, a large volume of water would escape at once and flooding could happen with little or no warning. If you live or work in an area that could be affected, you should plan in advance what you would do in an emergency. You may need to evacuate immediately. Consider where you would go to safety, and be ready to follow the advice of emergency services.
To find out about local emergency plans, contact the local authority listed when you click in the green shaded area on the map. Be aware that they may not be able to give you any specific information immediately as developing reservoir emergency plans is a new responsibility.