Advice on flood risk management for developers

The impact of flooding can be avoided and reduced through good planning and management, considering the:

• location
• nature of the development
• land use

Future climate change must also be considered to make sure what we are building now, does not affect us later.

1. Find out if your development is at risk of flooding

   Find out if your development is at risk of flooding and if it is:
   

   • in flood zone 1, 2 or 3
   • within 20 metres of a river or flood defence
   • in a water storage area
   • at risk from surface water flooding

   This will help you understand which of the validation requirements you need to submit to us as the Lead Local Flood Authority. Find out if your development is at risk of flooding on GOV.UK.                        

   You can also use our Flood risk asset map to find out if your site is at risk of flooding.

   Check our Strategic Flood Risk Assessment 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)
2. Understand the size of your development

   The size of your development will have an impact on the validation requirements you need to submit to us.                      

   Small development

   For developments that have less than 250 square metres of newly created drained surfaces, no flow restriction or on site attenuation is needed. This is only if the relevant sewer authority agree after your pre-planning sewer enquiry.                     

   The site should be drained with separate systems in accordance with Building Regulations. Find more information on Building Regulations on the Planning Portal. .                      

   You will need approval for any new connection to the public sewer through the Section 106 Water Industry Act 1990 Application from the relevant sewer owner, for example Yorkshire Water.                     

   If your development includes a front garden or driveway you should consider our front garden design guidance.                     

   You could also include some additional Sustainable urban Drainage (SuDS) features to help reduce the volume of surface water runoff from your site. Contact us for further guidance.                      

   Minor development

   This means:                     

   • 1 to 9 dwellings, less than 0.5 hectre
   • office, industrial and retail under 1 hectre
   • gypsy and traveller site with up to 9 pitches
   • any other non-residential development or building under 1000 square metres

   Major development

   This means:                     

   • 10 or more dwellings
   • office, industrial and retail over 1 hectre
   • gypsy and traveller sites with 10 or more pitches
   • any other non-residential building or development over 1000 square metres
3. Understand our validation requirements for each application type

   If you are applying for a minor or major development, you must submit evidence with your planning application of the measures taken to deal with:                     

   • surface water runoff
   • the management of, or reduction of flood risk within the proposed development site

   This evidence must be provided to support either an Outline, Full, Reserved Matters or Condition Discharge applications.                      

   The Flood Risk requirements table (PDF, 77KB) outlines what information should be submitted for each application type. This information should be provided to allow us to review the application in full and provide a faster decision.                     

   It is the applicant’s responsibility to make sure the relevant information is submitted in a suitable format. If all the relevant information is not provided, the application may not be validated.                      

                        

4. The Planning Application Process

   You will need to submit a Surface Water Drainage Strategy and a Flood Risk Assessment with your planning application.             

   1. A Surface Water Drainage Strategy should be submitted for all sites greater than 250 square metres.
   2. A Flood Risk Assessment should be submitted for all sites greater than 1 ha, within Flood zone 2 and 3, or at serious risk of flooding from other sources. This should be proportionate to the risk and appropriate to the scale, nature and location. It should take into account flooding from all sources as set out within Note 50 of para 163 of the National Planning Policy Framework on GOV.UK.

   The Surface Water Drainage Strategy and the Flood Risk Assessment should comply with our minimum development control standards for flood risk.