Almost one in four properties in England are based in areas at risk of flooding, data from the Environment Agency shows.
It says that 6.3 million properties are based in spots that may be overwhelmed by one, or a combination of, rivers, the sea and surface water.
The survey, which covers England’s 25 million homes, comes from the agency’s latest National Assessment of Flood Risk.
This document was last updated in 2018 and reports that 14.5% more homes face the threat of flooding.
The agency says around 4.6 million properties are in danger of flooding from surface water, where there is so much rainwater that drainage systems are overwhelmed, causing surface water runoff, also known as flash flooding. This is a 43% increase on its previous assessment.
Around 2.4 million properties are in areas that face flooding jeopardy from rivers and the sea.
The agency says: “There are a variety of reasons for this change in risk, the most notable being improved data and modelling methods for assessing the likely frequency of flooding.”
But adds that with climate change, the total number of properties in areas at risk from rivers and the sea or surface water could increase to around 8 million by 2050.
Environment Agency director of flood risk strategy Julie Foley says: “We have spent the last few years transforming our understanding of flood and coastal erosion risk in England, drawing on the best available data from the Environment Agency and local authorities, as well as improved modelling and technological advances.
“Providing the nation with the best available information on flood and coastal erosion risk is vital to ensuring that policymakers, practitioners and communities are ready to adapt to flooding and coastal change.”