The Environment Agency has today published a major update to national flood and coastal erosion risk assessment showing 6.3 million properties across England are in areas at risk of flooding from one or a combination of rivers, the sea and surface water.

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 the middle of the century – or around one in four properties.

Around 4.6 million of those properties are in areas at risk 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 the Environment Agency’s previous assessment.

These changes are almost entirely due to significant improvements in the Environment Agency’s data, modelling and use of technology providing a more accurate assessment of surface water flood risk.

Around 2.4 million properties are in areas at risk of flooding from rivers and the sea. While the total number of properties at risk is not increasing, there is an 88% increase in the number of properties at the highest levels of risk, where an area has a greater than one in 30 chance of flooding in any given year. 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.

Using the best available data from both the Environment Agency and local authorities, the new National Assessment of Flood Risk (NaFRA) provides a single and updated picture of the current and future flood risk from rivers, the sea and surface water for England. The last update to NaFRA was in 2018.

Alongside this, the Environment Agency has also updated the National Coastal Erosion Risk Map (NCERM) for the first time since 2017. This provides the most up to date national picture of the current and future coastal erosion risk for England using the best available evidence from the National Network of Regional Coastal Monitoring Programmes.

The Environment Agency has used cutting-edge methods to create new, bespoke software to integrate detailed local flood risk models – both its own and those of local authorities – into a national picture. For the first time, both NaFRA and NCERM account for the latest UK climate projections from the Met Office.

The updated assessments provide a clearer understanding of flood risk around the country and the data will be used by the government, Environment Agency and local communities to plan for and improve flood resilience in areas at risk.

The Agency’s updated assessment also shows how coastal erosion risk is changing across our shorelines, with 3,500 properties expected to be in areas at risk of coastal erosion in the period up to 2055, increasing to about 10,100 properties by the end of the century.

Julie Foley, Director of Flood Risk Strategy at the Environment Agency said:

“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.

“Our updated assessment shows there are 6.3 million properties in England in areas at risk of flooding from rivers, the sea or surface water. When we account for the latest climate projections, one in four properties could be in areas at risk of flooding by the middle of the century.

“Providing the nation with the best available information on flood and coastal erosion risk is vital to ensuring that policy makers, practitioners and communities are ready to adapt to flooding and coastal change.”

Hannah Bartram, Association of Directors for Environment, Planning and Transport (ADEPT), said that more detailed flood and coastal risk information, which takes climate change into account, is essential for local authorities to be able to plan effectively, to protect their local communities and to start to build resilient infrastructure for the future.

Stewart Rowe, Chair of Coastal Group Network echoed this view, saying:

“We welcome the collaborative effort the Environment Agency has taken to working with coastal authorities and coastal partners around the country to develop the new National Coastal Erosion Risk Map. It uses 10 years of evidence on coastal processes from the National Network of Regional Coastal Monitoring Programmes.

“The updated coastal erosion risk information will be critical to the implementation of the Shoreline Management Plans that set out our long-term approach to managing flood and coastal erosion risk around the coast.”

Alongside the Environment Agency’s role in providing information through flood risk mapping, the organisation is also responsible for the operation and management of flood risk assets. It is currently delivering the government’s long-term funding programme of flood defences, investing over £1 billion this year to scale up national resilience through building new and improving existing flood defences.

The Environment Agency remains committed to a rolling programme of data improvements to account for the latest local modelling evidence and national data. All the new NaFRA and NCERM data will be published and detailed local mapping will be made available from early 2025, to help decision-makers and communities understand what this new information means for them.

The Environment Agency will also update its digital services in early 2025, the key one being Check your long term flood risk for an area in England. This service is used by the public to identify the long-term flood risk for their area.

In spring 2025, the Environment Agency will update its Flood map for planning, used by planners and developers to find the data they need to undertake a flood risk assessment for a planning application.

The Environment Agency is currently developing a new flood and coastal investment programme using the best available evidence, including the new NaFRA and NCERM, allowing it to provide reassurance that its investment programmes are prioritising the places and projects where current and future risk is greatest.

NIC “Government must make full use of updated evidence to properly quantify risk and issue clear targets for cost effective risk reduction

Professor Jim Hall, Commissioner at the National Infrastructure Commission, said:

“Understanding the risk we face from flooding and coastal erosion is essential for building a long term strategy that addresses it effectively. This new mapping now gives us a more detailed profile of flood and coastal risks, providing a stronger basis for directing future strategic interventions and investment to the highest priority areas; it also means communities will have the information they need to take additional action to improve their own resilience.

“Government must now make full use of this updated evidence, and the Environment Agency’s own investment plans and data, to properly quantify the risk and issue clear targets for cost effective risk reduction along the lines the Commission has recommended.

“The new data showing the significant increase in properties at risk from surface water flooding also demonstrates the need for further action to stop the problem getting worse, including government implementing Schedule 3 of the 2010 Flood and Water Management Act and using its powers to control the spread of impermeable surfaces.”