Guidance

Review individual flood risk assessments: standing advice for local planning authorities

Find out when to use standing advice on site-specific flood risk assessments, and when to consult the Environment Agency.

For some developments you must consult:

For other developments you must use the flood risk standing advice in this guide.

Planning applicants can find advice on how to prepare a flood risk assessment and follow standing advice in preparing a flood risk assessment: standing advice.

Local planning authorities can find advice on how to complete a strategic flood risk assessment in the strategic flood risk assessments guide.

Research the development site

  1. Check the Environment Agency flood map for the flood zone the development is in and whether it’s within 20 metres (m) of a main river.
  2. Find out whether the development is in an area with critical drainage problems on data.gov.uk. Contact the Environment Agency if you are unsure.
  3. Establish the size of the development, including whether it’s major development on legislation.gov.uk.
  4. Find out the vulnerability classification.
  5. Use the following guidance to work out whether you need to consult or follow the standing advice.

When to consult the lead local flood authority

For major development with surface water drainage, consult your lead local flood authority (LLFA).

For other developments with surface water drainage you should check if there is:

  • a local consultation arrangement with your LLFA
  • local guidance on sustainable drainage systems you should follow

For more vulnerable developments on land at risk of other sources of flooding, such as surface water flooding:

  • the applicant should provide a flood risk assessment
  • check if there is a local consultation arrangement with your LLFA
  • ask your LLFA if you should consult it

Flood zone 1

When to consult the Environment Agency

Consult the Environment Agency if the development is:

  • within 20m of a main river on the Environment Agency flood map
  • in an area with critical drainage problems, other than minor development - check if your development is classed as minor development on legislation.gov.uk

Check your strategic flood risk assessment to see if the site will be at increased risk of flooding from rivers or the sea in future. If it will be, you should:

  • ensure a flood risk assessment is done
  • assess the site as if it were in flood zone 2

Flood zone 2

When to consult the Environment Agency

Consult the Environment Agency if the development (including change of use) is:

  • within 20m of a main river on the Environment Agency flood map
  • if the development’s flood risk vulnerability classification is:
    • ‘essential infrastructure’
    • ‘highly vulnerable’
    • ‘more vulnerable’ and it’s a landfill, waste facility site, caravan or camping site
    • ‘less vulnerable’ and it’s a waste treatment site, mineral processing site, water treatment plant, or sewage treatment plant

When to follow standing advice

Refer to the standing advice for vulnerable developments for developments (including change of use) with a flood risk vulnerability classification of:

  • ‘water compatible’ including essential accommodation within a water compatible development
  • ‘more vulnerable’ and not a landfill, waste facility site or a caravan or camping site
  • ‘less vulnerable’ and not a waste treatment site, mineral processing site, water treatment plant, or sewage treatment plant

Advice for minor extensions

Refer to advice for minor extensions for household or non-domestic extensions with a floor space of no more than 250 square metres.

Flood zone 3

When to consult the Environment Agency

Consult the Environment Agency:

  • within 20m of a main river on the Environment Agency’s flood map
  • for all developments other than minor development - check if your development is classed as minor development on legislation.gov.uk
  • for developments involving a change of use and the flood risk vulnerability classification will:
    • be either ‘more vulnerable’ or ‘highly vulnerable’
    • change from ‘water compatible’ to ‘less vulnerable’

Advice for minor extensions

Refer to advice for minor extensions for household or non-domestic extensions with a floor space of no more than 250 square metres.

What you need to check in an assessment

When reviewing flood risk assessments, you should look at:

  • how flood risk affects the proposed development
  • whether the development type is inappropriate for the proposed location
  • whether the measures proposed will make the development safe throughout its lifetime
  • whether the proposed development will be appropriately flood resistant and resilient
  • whether the proposed development will increase flood risk elsewhere

Refer to preparing a flood risk assessment: standing advice to help you check whether:

  • flood risk assessments contain all the information you need
  • the applicant has followed the standing advice
  • the applicant has met the extra flood resistance and resilience requirements where necessary

The sequential and exception tests

Check whether the sequential test and the exception test need to be applied.

The applicant needs to provide the evidence you need to check if the sequential test is required and if it has been satisfied.

If the sequential test has been satisfied you need to check if the exception test needs to be done as well. The exception test should be done for developments with a flood risk vulnerability classification of:

  • ‘highly vulnerable’ in flood zone 2
  • ‘more vulnerable’ in flood zone 3a
  • ‘essential infrastructure’ in flood zone 3a or 3b

You should refuse permission if the tests have not been done when required or have not been satisfied.

Contact the Environment Agency

Environment Agency

PO Box 544


Rotherham
Yorkshire
S60 1BY

Published 15 April 2015
Last updated 26 February 2021 + show all updates
  1. Guidance reviewed and no changes made.

  2. Correcting an omission in ‘The sequential and exception tests’ section. Flood zones have been reinstated for the ‘highly’ and ‘more’ vulnerable flood risk vulnerability classifications for when an exception test should be done.

  3. Clarity improved and links updated. Clarified status of advice for minor extensions and change of use categories. Moved ‘extra resistance and resilience measures’ section to 'Preparing a flood risk assessment: standing advice' guide. Included advice for areas of flood zone 1 that will be at future risk.

  4. Changed URL for "Find out what flood zone you’re in" to pint to new Flood Map for Planning service Changed URL for "Check if your development is within 20 metres (m) of a main river" to point to WIYBY Main River map

  5. First published.