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SAB Advice and Guidance

From January 7th 2019, all new developments of at least 2 properties or over 100m2 of construction area will require sustainable drainage to manage on-site surface water. The Surface water drainage systems must be designed and built in accordance with the mandatory standards for sustainable drainage published by Welsh Government.

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

Which legislation are we referring to?

Schedule 3 of the Flood and Water Management Act (FWMA) 2010 requires surface water drainage for new developments to comply with mandatory National Standards for sustainable drainage (SuDS). The statutory standards have been published by Welsh Government and can be accessed via the following link. Statutory National Standards for SuDS in Wales

Schedule 3 also places a duty on local authorities as SuDS Approving Body to approve, adopt and maintain systems compliant with section 17 of the Act. For further information on the legislation, please go to Schedule 3 of the Flood & Water Management Act

Guidance on Schedule 3 of the Flood and Water Management Act 

Welsh Assembly Government have drafted guidance to assist Local Authorities and Developers better understand the process. The guidance document provides vital information on the new regulations and can be found using the link below.

What exactly is a SAB?

The SAB is a service delivered by the local authority to ensure that drainage proposals for all new developments of at least 2 properties or over 100m2 of construction area are fit for purpose, designed and built in accordance with the national standards for sustainable drainage published by Welsh Ministers.

The SAB is established to:

  • Provide a Pre-application service to discuss your proposal
  • Evaluate and approve drainage applications for new developments where construction work has drainage implications, and
  • Adopt and maintain surface water drainage systems according to Section 17 of Schedule 3 of the Flood and Water Management Act.

What does it mean for my development?

Whether you are a developer, an agent or an individual seeking planning permission for a development, if your development is of 2 properties or more or a development where the impermeable surfaces are 100m2 or greater, you must seek SAB approval independently from your planning application. Construction can only begin once the SAB technical approval has been granted.

Existing sites and developments with planning permission granted or deemed to be granted (whether or not subject to any conditions) or for which a valid application has been received but not determined by 7 January 2019, will not be required to apply for SAB approval.

However, SAB approval will still be required if the planning permission was granted subject to a condition and an application for discharge of the condition is not made before 7 January 2019.

How do I seek SAB approval?

The SAB will offer a chargeable Pre-application service to discuss in detail your site, drainage requirements and what needs to be submitted with your application. While this process will be separate from the planning application process, discussion and consultation between the Local Planning Authority (LPA), the SAB and the developer will need to take place from the Pre-application stage to ensure suitability of proposed SuDs design in line with national standards, adequate site layout and ultimately SAB approval. This service which will be paramount to help limit delays to approval and reduce cost in the long term is strongly encouraged before submitting your full application. 

The application forms and adjoining documentation will be available for download from the SAB page of the Merthyr Council website from January. All submissions will need to be made to the relevant SAB as these cannot be completed or submitted via the Planning Portal.

How do I contact my SAB?

If you would like more information about the new legislation, please contact Merthyr Tydfil CBC's  SAB Officer using the details below:


Tel: 01685 725000

There is a large amount of information available and the following web pages are a useful free resource to gain more information on Sustainable Drainage and help you understand what you will need to consider: