Understanding and assessing flood risk

A flood risk assessment (FRA) is required for all development (including change of use):

• within Flood Zones 2, 3 or 3b
• within Flood Zone 1 with a site area of 1 hectare or more
• within Flood Zones plus Climate Change
• within areas with critical drainage problems
• within Flood Zone 1 where your LPA's SFRA shows it will be at risk of flooding from rivers or the sea in future
• that increases the vulnerability classification¹ and is in Food Zone 1 where your LPA's SFRA or the Flood Map for Planning² show it is may be subject to sources of flooding other than rivers or sea

If an FRA is required, the LPA can refuse planning permission if you don’t provide one, or if the FRA you provide is inadequate.

1. https://www.gov.uk/guidance/national-planning-policy-framework/annex-3-flood-risk-vulnerability-classification
2. https://flood-map-for-planning.service.gov.uk/