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Sustainable Drainage System Approval Body

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A significant change to drainage requirements.
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Since 7 January 2019, all new developments now require sustainable drainage for surface water if there are at least 2 properties or the construction area is more than 100m2. The surface water drainage systems must be designed and built to meet Welsh Government standards for sustainable drainage.

These systems must be approved by the local authority acting in its SuDS Approving Body (SAB) role before construction work begins. The SAB will have a duty to adopt compliant systems.

What is the new legislation?

The legislation is called Schedule 3 of the Flood and Water Management Act (FWMA) 2010. It requires surface water drainage for new developments to comply with compulsory National Standards for sustainable drainage (SuDS). The Welsh Government published the statutory standards in autumn 2018. We also recommend that you refer to the Statutory instruments and Statutory National Standards and CIRIA 753: The SuDs Manual.

Schedule 3 also requires local authorities as SuDS Approving Bodies to approve, adopt and maintain systems which comply with the Act. For more information on the legislation, please see Schedule 3 of the Flood & Water Management Act

What exactly is a SAB?

The SuDS Approving Body (SAB) is a statutory function delivered by the Council to make sure that drainage proposals for all new developments (with at least 2 properties or a construction area more than 100m2) are fit for purpose. The SAB makes sure that drainage is designed and built according to the national standards for sustainable drainage published by Welsh Government.

The SAB:

  • provides a pre-application service to discuss your proposal
  • evaluates and approves drainage applications for new developments where construction work has drainage implications, and
  • adopts and maintains surface water drainage systems
  • also has powers to inspect systems and take enforcement action where required

What does it mean for my development?

The law applies whether you are a developer, an agent or an individual seeking planning permission for a development. If your development has 2 properties or more or if the construction area is over 100m2 you must seek SAB approval separately from your planning approval. Construction can only begin once both permissions have been granted.

You do not have to apply for SAB approval if your existing site or development has:

  • planning permission granted before 7th January 2019
  • planning permission deemed to be granted (with or without any conditions about a reserved matter)
  • a valid application which has been received by the planners by 7th January 2019, but hasn’t yet been decided

You do have to apply for SAB approval if your existing site or development:

  • has planning permission granted subject to a condition about a reserved matter, and you haven’t made an application for approval of the reserved matter before 7 January 2020.

Does this apply to all developments?

You do not have to apply for SAB approval if:

  • your development does not need planning permission and the construction area is less than 100m2
  • Your development is for a single dwelling house, or other type of construction, which covers an area of land less than 100m2

How do I get approval from SAB for my drainage?

The Conwy SAB offers a pre-application service to discuss in detail your site, drainage requirements and what needs to be submitted with your application. There is a fee for this service.

This process is separate from the planning application process. However, there needs to be discussion and consultation between the Local Planning Authority (LPA), the SAB and the developer from the pre-application stage onwards. This is to make sure the proposed SuDs design is suitable in line with national standards, adequate site layout and finally, SAB approval. We strongly recommend that you use this service before you submit your full application, to limit delays to approval and reduce cost in the long term. 

Ask us for application forms and documentation. You need to make submissions directly to Conwy SAB because you cannot complete or submit them via the Planning Portal.

How do I contact Conwy SAB?

The start date for the approvals requirement was 7 January 2019.  Our new service is available to deal with your applications. 

If you would like more information about this new process, please contact us at

These webpages are a useful free resource to find out more information on Sustainable Drainage and help you understand what you will need to think about:

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