Guidance

Flood risk assessments: applying for planning permission

Find out when you need to do a flood risk assessment as part of your planning application, how to complete one and how it is processed.

From:
Environment Agency
Published
26 March 2014
Last updated
10 April 2025 바카라 사이트� See all updates

Applies to England

This guidance is for planning applicants.

Local planning authorities (LPAs) should use the聽National flood risk standing advice for local planning authorities when reviewing flood risk assessments.

As a planning applicant, you may need to carry out a flood risk assessment (FRA) for your proposed development site.

You will usually need to pay a flood risk specialist to carry out a聽FRA聽for you. An exception to this may be if it is for a simple, low risk development, for example, a house extension. In this case you may be able to do it yourself. If you are not sure,聽contact the Environment Agency聽for advice.

Your聽聽may refuse your聽application if you do not include a聽FRA聽or if it is not satisfactory.

When you need a flood risk assessment

You should complete a聽FRA聽for all development (including聽minor development聽and changes of use) proposed:

  • in Flood Zones 2 or 3 or see
  • within Flood Zone 3b
  • within Flood Zone 1 with a site area of 1 hectare or more
  • within Flood Zone 1 and the shows it is at increased risk of flooding from rivers or sea during its lifetime
  • with Flood Zone 1 and the shows it is at risk of flooding from surface water
  • in areas with critical drainage problems
  • within Flood Zone 1 where the LPA바카라 사이트檚聽strategic flood risk assessment (SFRA)聽shows it will be at increased risk of flooding during its lifetime
  • that increases the聽vulnerability classification聽and may be subject to sources of flooding other than rivers or sea

When you need a sustainable drainage strategy and what to include

You need to include a sustainable drainage strategy if your application is for development:

  • which could affect drainage on or around the site
  • in an聽area at risk of flooding聽such as Flood Zones 2 or 3, or at risk of surface water flooding

You should include all the information set out in:聽

Your sustainable drainage strategy can be a separate document or be part of a聽FRA. Check to see if the LPA or lead local flood authority (LLFA) have local policies or guidance with additional requirements.

Research the development site

To access the right flood risk advice for your development, you need to complete all the following steps:

  • use the聽聽to find if the development is in Flood Zone 1, 2 or 3
  • use the바카라 사이트� to find if the development is at risk of surface water flooding
  • check the LPA바카라 사이트檚 SFRA to identify if the site is in Flood Zone 3b (functional floodplain)
  • find out the vulnerability classification - if you are unsure discuss this with your LPA and make it clear in your FRA
  • check聽Table 2 of the Planning Practice Guidance聽to find out if the proposed vulnerability classification is incompatible with the Flood Zone
  • check the and LPA바카라 사이트檚 SFRA to identify if the site is in Flood Zone 1 now but will be at risk of flooding from rivers or the sea during its lifetime
  • check the LPA바카라 사이트檚 SFRA to identify if the site is at risk from any other source of flooding or it will be during its lifetime
  • refer to聽check the long term flood risk for an area in England聽to identify if your site is at risk of flooding from groundwater (where data is available) or reservoirs
  • refer to check the long term flood risk for an area in England바카라 사이트痶o identify if your site is at future risk of flooding from surface water (note the time horizon and climate change scenario for surface water fall short of what바카라 사이트檚 needed for planning so additional assessment may be needed)
  • check if the site is in an 바카라 사이트� these are currently only designated in and and the Environment Agency has provided local standing advice for these areas
  • establish the site area (in hectares) 바카라 사이트� the can help you do this
  • check whether the development is바카라 사이트�
  • check if your development is a minor extension
  • follow the guidance on shown on the flood map for planning

A minor extension is a household or non-domestic extension with a floor space of no more than 250 square metres.

In some cases, SFRAs may not hold suitable information for your site on functional floodplain. In such cases, your FRA will need to provide suitable information. To inform your assessment of functional floodplain you could refer to the following information on :聽

  • present day 3.3% annual probability extent of river and sea flooding with defences聽
  • water storage areas

You should always review these datasets to check they are suitable for identifying functional floodplain in each location.

Note that check the long term flood risk for an area in England also shows the risk of flooding from rivers and sea. However, this information is different to the Flood Zones shown on the . This means you should not use it for development planning.

Access the right advice

Follow the Environment Agency바카라 사이트檚聽advice for minor extensions聽if you are doing a聽FRA聽for a minor extension in Flood Zone 2, 3 or 3b.

Follow the Environment Agency바카라 사이트檚聽standing advice for vulnerable developments聽if you are doing a聽FRA聽for a development (including change of use) in Flood Zone 2 classed as:

You should follow聽standing advice for vulnerable developments聽for change of use development in Flood Zone 3 聽where the vulnerability classification will:

  • be 바카라 사이트榳ater compatible바카라 사이트�
  • remain unchanged as 바카라 사이트榣ess vulnerable바카라 사이트�

Also follow local flood risk standing advice for development (including change of use) if your site is in an 바카라 사이트� these are currently only designated in and . Contact the LPA for a copy of the local standing advice.

For all other development types requiring a FRA in Flood Zones 1, 2, 3 or 3b, you need to follow the advice in Flood risk assessment: Flood Zones 1, 2, 3 and 3b聽聽

If your site is in Flood Zone 1 but the or your聽LPA바카라 사이트檚聽SFRA聽shows it will be at increased risk of flooding from rivers or the sea during the development lifetime, you should:

  • make sure a聽FRA聽is done
  • treat the site as if it were in Flood Zone 2 when deciding which advice you need to access

Get information about flood risk from rivers and the sea to help you to complete a聽FRA

The Environment Agency has information which will help you complete your flood risk assessment.

This includes information on:

  • flood risk from rivers and the sea and about flood risk management structures and features
  • how climate change will affect flood risk from rivers and the sea in future
  • residual flood risk in some locations to help you assess the consequences of flood defences being breached or overtopped

This information will help you calculate the estimated flood level for your site in the design flood and assess residual flood risks. Please note that the design flood and residual risks must include an appropriate allowance for climate change.

These products or packages of information are available from the Environment Agency바카라 사이트檚 :

Product 1

This product is a copy of the flood map which shows:

  • Flood Zones 1, 2 and 3
  • defences
  • statutory main river designations
  • water storage areas

Product 3

This product has been discontinued. Relevant information is now available through other products.

Product 4

This product is a detailed聽FRA聽map. Where available, it shows:

  • detailed flood data
  • flood defence locations and attributes
  • data on past flood events
  • modelled flood levels and extents
  • flood defence breach hazard information

The models show the model extents and modelled flood levels and flows at several specific points. This could either be within the river channel or, if available, in the floodplain.

Product 5

This product is a report which includes flood modelling and hydrology reports.

Product 6

This product is the model output data and all the reports in product 5.

Product 7

This product is the Model Input Data, and all the reports in product 5. This represents the best available modelled data we have for the area. You will need to assess any model to make sure it is suitable for your FRA.

Product 8

Flood defence breach hazard information. This information will be included in Product 4 where it is available.

Choose the correct product

For all development you should request product 1 and product 4.

If your聽FRA聽will use detailed hydraulic modelling held by the Environment Agency, you are also likely to need products 5, 6 and 7. Refer to Using modelling for flood risk assessments for guidance on when to use modelling and the expected standards.

Understand limitations of using existing models

Material displayed on the is provided without any guarantees, conditions or warranties as to its accuracy. This includes maps and risk data. See our바카라 사이트�바카라 사이트痜or more information.

It바카라 사이트檚 your responsibility to check the suitability of an existing model for your development.바카라 사이트�

If you use an existing model from the Environment Agency or another organisation, it is important to check if it:바카라 사이트�

  • represents current risk바카라 사이트�
  • uses the latest available datasets바카라 사이트�
  • complies with current modelling standards바카라 사이트�
  • is at a scale suitable for the assessment you are undertaking바카라 사이트�
  • captures the detail required for a site-specific assessment바카라 사이트�
  • makes use of current climate change allowances바카라 사이트�

바카라 사이트痀ou should be aware that:바카라 사이트�

  • Environment Agency models are not designed to assess third party developments, so do not assume that they are suitable for your proposed development바카라 사이트�
  • even if you use a recent model, you still need to review and possibly update it바카라 사이트�
  • you should provide evidence of any modelling checks and subsequent updates you carry out and record these in the바카라 사이트�FRA바카라 사이트痬odel reporting바카라 사이트�
  • you should refer to the Environment Agency바카라 사이트檚바카라 사이트�standard model and hydrology review templates바카라 사이트痺hen carrying out your model review

How to get or order the products

For all the products you need to use the聽. Find the correct area by entering the postcode or location of the development site. Then you can draw the boundary of your site to get relevant flood risk information.

For product 1, which is a copy of the flood map for planning for your development site, you can download a copy of the map.

For product 4 - input your name and email address on the page for your development site and submit it. The local Environment Agency team will send product 4 information to you for that location within 20 working days.

For products 5, 6 and 7, you need to find the contact details for the local Environment Agency office and send a request to them. You can find these details in the flood map for planning on the page of your chosen development site.

Get information about other sources of flood risk to help you complete a flood risk assessment

You need to consider all sources of flood risk in your聽FRA. You can get information on surface water flood risk from the . You can get additional information on surface water, groundwater (where available) and reservoir flooding by referring to聽Check the long term flood risk for an area in England. You may be able to get other information on flood risk, by contacting the:

  • LLFA
  • LPA聽for information from its聽SFRA
  • water and sewerage company
  • internal drainage board if you are in an 聽

Contact the Environment Agency

If you would like more detailed, site-specific advice on flood risk, such as a review of your draft FRA, visit How to request Environment Agency advice.

Updates to this page

Published 26 March 2014
Last updated 10 April 2025 show all updates

  1. Amended to signpost to new guidance on how to use the flood risk datasets shown on the Flood Map for Planning. Provided additional guidance to ensure FRAs appraise the suitability of flood risk datasets before use and understand the limitations of existing models.

  2. Amended to signpost new flood and coastal erosion risk data and provide advice on its use, updated to reflect new functionality of the flood map for planning and clarified response times for Product 4 requests

  3. Updated the 'Access the right advice' section with 'where the Environment Agency should be consulted' and 'treat the site as if it were in flood zone 2 when deciding which advice you need to access'

  4. Amended title, removed discontinued products, added detail on how to research the development site, added links, updated and improved clarity of other sections.

  5. Changed URL "Find out what flood zone you're in" to the new Flood Map for Planning digital service

  6. Information about charges for products removed.

  7. Clarified flood risk product 8 should be used in an area behind raised flood defences in zone 3.

  8. Flood risk product information added.

  9. First published.

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