Understanding and assessing flood risk

1) Use the Environment Agency Flood Map for Planning¹ to find if the development is:

• in Flood Zone 1, 2 or 3
• in Flood Zones plus Climate Change
• within 20 metres of a main river or a flood defence
• in a water storage area
• in Flood Zone 1 and at risk of flooding from surface water

You can also order additional Environment Agency flood risk data through the Flood Map for Planning².

2) Find out whether the development is in an area with critical drainage problems³. 
Please note that areas with critical drainage problems are currently only designated in Devon and Cornwall.

3) Check your LPA’s strategic flood risk assessment (SFRA) to find out if the development is:

• in Flood Zone 1 now but will be at risk of flooding from rivers or the sea during its lifetime
• subject to sources of flooding other than rivers or sea or it will be during its lifetime
• in Flood Zone 3b (functional floodplain)

4) Establish the site area and check the development class

5) Find out the vulnerability classification⁴

6) Check table 2 of the planning practice guidance⁵ to find out if the proposed vulnerability classification is incompatible with the Flood Zone.

1. https://flood-map-for-planning.service.gov.uk/
2. https://flood-map-for-planning.service.gov.uk/
3. https://data.gov.uk/dataset/d10fb8e5-f3af-48c1-a489-8c975b0165de/areas-with-critical-drainage-problems
4. https://www.gov.uk/guidance/national-planning-policy-framework/annex-3-flood-risk-vulnerability-classification
5. https://www.gov.uk/guidance/flood-risk-and-coastal-change#table2