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Understanding and assessing flood risk

Check whether any other permissions or consents are needed

You may also need a separate permit or consent if the development or any associated works (e.g. site preparation or construction):

  • are within 20 metres of a main river, a flood defence or flow control structure
  • directly affect a watercourse that is not a main river
  • involve activity (e.g. land raising) in the floodplain of a main river which could affect flood flow or storage, and potential impacts are not controlled by a planning permission

Check if you need permission to do work on a river, flood defence or sea defence1. Do this as soon as possible to make sure you can get the necessary permissions.

If there is a watercourse (including culverted watercourses) on or near your site, you should also read Owning a watercourse2 to understand your responsibilities and the rules you need to follow. A culvert is an underground structure that water can flow through.

Flood risk permits or consents are often needed as well as planning permission. Getting planning permission does not guarantee you’ll also get a flood risk permit or consent.


Further information

  1. https://www.planningportal.co.uk/permission/responsibilities/other-considerations-before-you-start-work
  2. https://www.planningportal.co.uk/permission/responsibilities/other-permissions-you-may-require
  1. https://www.gov.uk/permission-work-on-river-flood-sea-defence
  2. https://www.gov.uk/guidance/owning-a-watercourse

The Planning Portal is delivered by PortalPlanQuest Limited which is a joint venture between TerraQuest Solutions Limited and the Department for Levelling Up, Housing & Communities. All content © 2022 Planning Portal.

The Planning Portal is delivered by PortalPlanQuest Limited which is a joint venture between TerraQuest Solutions Limited and the Department for Levelling Up, Housing & Communities. All content © 2022 Planning Portal.