Drainage for major developments

What you need to provide

 When applying for planning permission for a major application you'll need to:

  • complete a drainage assessment form
  • provide detailed drainage design plans
  • check to see if you need to provide a flood risk assessment 

Drainage assessment form

In this form you can tell us:

  • the site’s characteristics
  • the calculated surface water runoff rates and required storage volumes
  • where the runoff is to be discharged to
  • the sustainable drainage systems (SuDS) features proposed
  • how the drainage system is going to be managed and maintained

In your application, you'll need to show that the excess runoff will be managed effectively and not cause an increase in flood risk anywhere else, ie both to and from the site.

You'll also need to agree a plan with us which sets out an adoption and maintenance program for the SuDS over the duration of the development’s lifetime.

Download the drainage assessment form. Print it, complete it and return it with your application for planning permission.

Flood risk assessment 

Check the National Planning Policy Framework (chapter 10, footnote 20) to see if you need to provide a flood risk assessment.

What we do

As the Local Lead Flood Authority, we'll assess your application against local and national policies in line with our Statutory Consultee duty.