Guidance

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

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

Applies to England

For some developments you must consult:

  • the Environment Agency
  • the lead local flood authority (LLFA)
  • or both

For other developments you must use the flood risk standing advice in this guide. This guide applies to the following application types:

  • full
  • outline
  • reserved matters
  • change of use
  • prior approval for flood risk under certain permitted development rights
  • permission in principle
  • technical details consent

You must also consult the Environment Agency on a range of other issues. These are set out in Schedule 4 of the Development Management Procedure Order, 2015 (DMPO). This standing advice is for DMPO Schedule 4 paragraphs ‘t’ and ‘zc’ only.

Planning applicants can find advice on preparing a flood risk assessment: standing advice.

Local planning authorities can find advice on how to prepare a strategic flood risk assessment (SFRA).

Research the development site

  1. Use the Environment Agency flood map to find if the development is:

    • in flood zone 1, 2 or 3
    • within 20 metres of a main river or a flood defence
    • in a water storage area
  2. Find out whether the development is in an area with critical drainage problems. Contact the Environment Agency if you are unsure.

  3. Check your 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
    • at risk from any other source of flooding 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 classification.

  6. Use the following guidance to work out whether you need to consult or follow the standing advice.

Check the development class

Major development involves one or more of the following:

  • providing 10 or more dwellinghouses (defined in article 2 of the DMPO) or, where the number of dwellinghouses is not known, the site area is 0.5 hectares or more
  • providing a building or buildings where the floor space to be created by the development will be 1,000 square metres or more
  • development on a site of 1 hectare or more
  • the winning and working of minerals or the use of land for mineral-working deposits
  • waste development

A minor development is:

  • development of an existing dwellinghouse, or development within the curtilage of a dwellinghouse, for any purpose incidental to the enjoyment of the dwellinghouse
  • an extension to an existing building used for non-domestic purposes where the floor space created by the development does not exceed 250 square metres
  • alterations to an existing building which do not increase the size of the building

Non-major development is any development not falling into the major or minor development classes.

Check if a flood risk assessment is needed and if one is provided

Before validating the application, you should check if a flood risk assessment (FRA) is needed and if one is provided. A FRA is required for all development:

  • within flood zones 2, 3 or 3b
  • within flood zone 1 with a site area of 1 hectare or more
  • within areas with critical drainage problems
  • within flood zone 1 where your SFRA shows it will be at risk of flooding from rivers or the sea in future
  • that increases the vulnerability classification and is in flood zone 1 where your SFRA shows it is at risk from other sources of flooding

The FRA should be:

  • appropriate to the scale, nature and location of the development
  • proportionate to the degree of flood risk

It should contain the information set out in the site-specific flood risk assessment check-list. To check the FRA contains the correct information, you should follow the guidance in preparing and checking a flood risk assessment: standing advice.

Check if information on sustainable drainage systems is needed and if it is provided

Before you validate the application, you should check if information on sustainable drainage systems is needed and if it is provided.

Information on sustainable drainage systems is needed for all:

  • major development with surface water drainage
  • development with surface water drainage in an area at risk of flooding such as flood zones 2 or 3, or at high risk of surface water flooding

You should include all the information set out in section 6 of the site-specific flood risk assessment checklist. You can put it in a separate document or in the FRA. Check to see if you (or the LLFA) have local guidance with additional information requirements.

The sequential and exception tests

A sequential test is required for major and non-major development (check the development class section above) if it is:

  • in flood zone 2 or 3
  • in flood zone 1 and your SFRA shows it to be at risk of flooding from rivers or the sea in the future
  • at risk of flooding from other sources, or could be in the future

Development in flood risk areas is only exempt from the sequential test if it is a:

  • householder development like residential extensions, conservatories or loft conversions
  • small non-domestic extensions with a footprint of less than 250 square metres
  • change of use (except changes of use to a caravan, camping or chalet site, or to a mobile home or park home site)
  • development on a site allocated in the development plan through the sequential test, and the proposal is consistent with the site’s allocated use

If the sequential test is satisfied you need to check if the exception test is needed. The exception test is needed for developments with a vulnerability classification of:

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

The applicant needs to provide the evidence you need to check if both of the following apply:

  • the sequential and exception tests are required
  • they have been satisfied

You should refuse permission if the sequential and exception tests are not done or not satisfied.

When to consult the lead local flood authority

For major development with surface water drainage, consult your 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 developments that will increase the vulnerability classification and where your SFRA shows it is at risk from other sources of flooding:

  • the applicant should provide a FRA
  • 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 proposed development (including change of use) is:

Check your SFRA 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 FRA is done
  • apply this guidance as if the site 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 proposed within 20 metres of a main river
  • other than minor development, (check the development class in the above section) will have a vulnerability classification of:

    • ‘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) that will have a 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

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 or 3b

When to consult the Environment Agency

Consult the Environment Agency on:

  • development (including change of use) proposed within 20 metres of a main river or flood defence
  • development other than minor development (check the development class in the above section)

  • changes of use where the vulnerability classification will:
    • be ‘more vulnerable’ or ‘highly vulnerable’
    • change from ‘water compatible’ to ‘less vulnerable’

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

Please note that table 3 of the planning practice guidance states you should not permit development in flood zone 3b if its vulnerability classification will be:

  • ‘highly vulnerable’
  • ‘more vulnerable’
  • ‘less vulnerable’

Tell the applicant about other permits or consents

You should tell the applicant to check if they need a separate permit or consent. They may need one if the development:

  • is within 20 metres of a main river, flood defence or flow control structure
  • directly affects a watercourse that is not a main river

If either of these apply to the development, tell the applicant to refer to check if you need permission to do work on a river, flood defence or sea defence. They should do this as soon as possible as it will tell them if they need an extra permit or consent and who to contact.

In some cases, we may recommend that the applicant applies for planning permission at the same time as other permits or consents. This will help to resolve complex permitting issues at the same time as decision making for the planning process.

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

What you need to check in an assessment

When reviewing FRAs, you should check whether:

  • all sources of flood risk affecting the proposed development now and throughout its lifetime have been assessed
  • the development type is inappropriate for the proposed location
  • the measures proposed will make the development safe throughout its lifetime
  • the proposed development will be appropriately flood resistant and resilient
  • the proposed development will increase flood risk elsewhere
  • the site has been laid out, so the most vulnerable aspects of the development are located in areas of lowest flood risk
  • any residual risks can be safely managed
  • safe access and escape routes are included where appropriate, as part of an agreed emergency plan
  • the proposed development incorporates sustainable drainage systems

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

  • FRAs 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
Published 15 April 2015
Last updated 8 February 2022 + show all updates
  1. Updated to improve clarity and reflect the latest National Planning Policy Framework. Clarified application types to which the standing advice applies. Included definitions for development classes to improve clarity. Improved links to strategic flood risk assessments. Greater clarity on the need for flood risk assessments, sustainable drainage information and sequential and exception test information. Highlight the need to check the compatibility of the proposed use with the flood zone. Highlighting that some developments may also need a flood risk activity permit.

  2. Guidance reviewed and no changes made.

  3. 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.

  4. 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.

  5. 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

  6. First published.