Sustainable drainage systems

Since January 2019, all new developments that:

• Include more than one building or
• Have a construction area of 100m2 or more

have to include sustainable drainage systems (SuDS) for surface water.

This is Welsh Government legislation, and is detailed in its schedule 3 of the Flood and Water Management Act 2010 which you can read in full here.

Traditional drainage systems can increase the risk of flooding. SuDS imitate the natural drainage process, meaning they lessen the risk of flooding.

What do you need to know? 

• If you’re developing a site of more than one building, you need to design it with a sustainable drainage system in mind.
• SuDS must be designed and built in accordance with the Welsh Government’s statutory standards.
• SuDS schemes must be approved by the SuDS Approving Body (SAB), before construction work begins.
• SABs are delivered by local authorities across Wales. Here’s a handy list of local authorities in our operating area – we’d recommend contacting them directly and asking to speak to their SAB team.

Blaenau Gwent County Borough Council

Bridgend County Borough Council

Caerphilly County Borough Council

Carmarthenshire County Council

Ceredigion County Council

City and County of Swansea

City of Cardiff Council

Conwy County Borough Council

Denbighshire County Council

Flintshire County Council

Gwynedd Council

Isle of Anglesey County Council

Merthyr Tydfil County Borough Council

Monmouthshire County Council

Neath Port Talbot Council

Newport City Council

Pembrokeshire County Council

Powys County Council

Rhondda Cynon Taf County Borough Council

Torfaen County Borough Council

Vale of Glamorgan Council

Wrexham County Borough Council

• Once you’ve applied to your local planning authority for approval, they will contact us to confirm that we can manage any new wastewater connections into our network.
• Once both the local planning authority and SAB have approved your design, it will then be adopted and maintained by the SAB.
• You don’t need to get SAB approval if:
  • Your development has drainage implications of a single house and the area of land covered by the construction work is less than 100m2, or
  • The area of land covered is less than 100m2 and involves any other type of construction work.

Want to know more? 

• Here’s a leaflet which will give you more information.
• You can also read the Welsh Government’s statutory SuDS standards.
• Still after more information? These two organisations may be able to help:
  • SuDS Wales
  • Susdrain

Don’t forget

• You might also be eligible for our surface water incentive scheme if you have plans to remove surface water from the wastewater network