What are Sustainable Drainage Systems

Sustainable drainage systems (SuDS) are designed to mimic natural drainage by managing surface water run-off as close to source as possible.

All new developments are now required to include Sustainable Drainage Systems which comply with National Statutory SuDS Standards. Developers must gain approval for their drainage from a SuDS Approval Body (SAB) before construction can begin.

SABs operate within all of the local authorities.

Download the National Statutory SuDS Standards from the Welsh Government website.

SAB Approval

SABs offer a chargeable pre-application service to discuss the individual site’s requirements and advise on submitting an application.

Applications should be submitted to the SAB for validation and accompanied by:

  • a plan specifying the construction area and the extent of the drainage system
  • information on how the construction work will comply with the SuDS Standards
  • information requested in the application form checklist
  • the appropriate application fee

SABs will respond within 7 weeks or 12 weeks if an Environmental Impact Assessment is required.


Susdrain is an independent website for those involved in delivering sustainable drainage. It provides guidance, information and case studies to help with the planning, design, approval, construction and maintenance of SuDS.

Support is available for flood risk managers, engineers, planners, designers, landscape architects and developers.

Read more about all aspects of SuDS on the Susdrain website.

Further guidance on SuDS

CIRIA produce ‘Guidance on the Construction of SuDS’ and ‘The SuDS Manual’, which can be downloaded free of charge from their website (log in required).

Welsh Government SuDS guidance

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