Sustainable drainage systems

From 7 January 2019 all new developments with a construction area of 100 square metres or more must have an approved sustainable drainage system (SuDS) to manage on-site surface water.

Surface water drainage systems must be designed and built following mandatory standards published by Welsh Government and must be approved by the council's Sustainable Drainage Approving Body (SAB) before work starts.

Sustainable Drainage Approving Body (SAB) 

The SAB is a statutory council function to ensure that drainage proposals meet the national standards. The SAB will:

  • provide pre-application advice to discuss drainage proposals
  • evaluate and approve drainage applications for new developments where construction work has drainage implications
  • adopt and maintain sustainable surface water drainage systems according to Section 17 of Schedule 3 (FWMA)

The SAB also has powers of inspection and enforcement.

Read Schedule 3 to the Flood and Water Management Act 2010 for further details.

SAB approval is separate to planning permission, you must make separate applications for each and will not be allowed to start construction until the two permissions are granted.   

You are advised to seek pre-application advice so that drainage requirements can be considered by the planning section and by the SAB. 

Exemptions include:

  • construction areas less than 100 m2
  • construction work that doesn’t require planning permission unless it covers an area of 100 m2 or more
  • existing sites with planning permission prior to 7 January 2019
  • sites for which a valid planning application has been received by 7 January 2019
  • sites for which outline permission has been granted by 7 January 2019 and an associated reserved matters submission is made by 7 January 2020

Ciria animation

Watch Ever Wondered Where the Rain Goes? from Ciria (construction industry research and information association)

Apply for SAB approval

We offer a chargeable pre-application advice service to discuss in detail your site’s drainage requirements and what needs to be submitted with your application.

This service is separate from the planning pre-application service.

Download and read SAB pre-application advice (pdf) before applying

Request SAB pre-application advice meeting

Request SAB pre-application advice

Full application fees range from £420 to £7,500 based on development size.

Download and read SAB full application advice (pdf) before applying.

SuDS full application

SuDS approval of conditions

The SAB has seven weeks to determine applications other than those requiring an Environmental Impact Assessment, in which case it has 12 weeks.

Please log in to My Council Services if you have a saved application form you’d like to continue. Once logged in, go to the “Draft service requests” section at the top right of the screen. To open the form, click the edit symbol to the left of the one you want to complete.

Further information

Read Welsh Government information about Sustainable drainage systems on new developments


Email [email protected] or telephone (01633) 656656

Read more information about sustainable drainage on the Susdrain site

TRA95282 17/12/2018