Flood risk assessments

Flood risk is a material planning consideration and it is the applicant’s responsibility to assess and mitigate that risk.

To find out whether land is within a flood risk zone you can use the flood map search on the Environment Agency's Floods - Flood Map and how to use it, or call them on 08708 506 506.

Legislation requires that Lambeth consults the Environment Agency in relation to certain planning applications, particularly those on land within flood risk zones.

For any application where we will need to consult the Environment Agency over flood risk, the applicant will be required to submit a flood risk assessment (FRA). The FRA must identify and assess the risks of all forms of flooding to and from the development and demonstrate how those flood risks will be managed, taking climate change into account. The assessment must also identify opportunities to reduce the possibility and consequences of flooding. You can find out more about flood risk assessments in Planning Policy Statement 25 (PPS25), in Planning Policy Statement 25: Development and Flood Risk Practice Guide and the Environment Agency's standing advice on flood risk.

Applications requiring an FRA are classified as follows:

• In flood zones 2 and 3, with all applications, other than minor* developments.
• In flood zone 1, all applications other than minor* developments, if the site has critical drainage problems.
• All applications for development of land of 1 hectare or more.
• All applications for development within 20 metres of a main river.
• All applications for development involving the culverting or control of flow of any river or stream.

*Minor developments in this context are defined as:

• Non residential extensions to an existing building where the floorspace created does not exceed 250 sq metres.
• Alterations to an existing building where the alterations do not increase the size of the building.
• Alterations and extensions to an existing dwelling-house, or development within the boundary of a dwelling-house, for any purpose incidental to the use of the dwelling-house.

If an application requires an FRA and it is and not submitted with the application, it may be treated as invalid until an assessment is provided. The Local Planning Authority can also refuse planning permission for development if the application is not submitted with a suitable assessment.