Sustainable Drainage Regulations

Significant change to drainage requirements will impact on new developments from January 2019

From 7 January 2019 all new developments of more than one house, or where the construction area is of 100m2 or more will require sustainable drainage to manage on-site surface water. Surface water drainage systems must be designed and built in accordance with mandatory standards for sustainable drainage published by Welsh Ministers. These systems must be approved by the local authority acting in its Sustainable Drainage Systems (SuDS) Approving Body (SAB) role before construction work begins. The SAB will have a duty to adopt compliant systems so long as it is built and functions in accordance with the approved proposals, including any SAB conditions of approval.

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 were published by Welsh Government on 15 October 2018 along with the Statutory Instruments, which can be found here: 

  • Welsh Government - Statutory Standards / Statutory Instruments - View here
  • Additional information available from CIRIA 753: The SuDs Manual - View here 

Schedule 3 to the FWMA 2010 also places a duty on local authorities as SuDS Approving Body to approve, adopt and maintain systems compliant with section 17 of the Schedule. For further information on the legislation please go to:

  • Schedule 3 of the Flood & Water Management Act 2010 View here 
What exactly is a SAB?

The SAB is a statutory function delivered by the local authority to ensure that drainage proposals for all new developments of more than one house, or where the construction area is 100m2 are designed and built in accordance with the national standards for sustainable drainage published by Welsh Ministers. The SAB is established to:

  • 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 and uses discretionary powers to offer non-statutory pre-application advice.

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 more than one house or of 100m2 or more of construction area you must also seek SAB approval alongside planning approval. You will not be allowed to start construction until the two permissions are granted.

Existing sites and developments with planning permission granted or deemed to be granted (whether or not subject to any conditions as to a reserved matter) 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 as to a reserved matter and an application for approval of the reserved matter is not made before 7 January 2020. 

Some exemptions will apply:

  • Construction work which does not require planning permission is excepted from the requirement for SAB approval, the exception does not apply where the construction covers an area of 100 m2 or more
  • Whether or not planning permission is required, construction work involving the construction of a single dwelling house, or other type of construction, which covers an area of land of less than 100m2, is excepted from the requirement for approval
How do I seek SAB approval?

The SAB will offer a chargeable pre-application service to discuss in detail your site’s drainage requirements and what needs to be submitted with your application. This service is different from the planning pre-application service, so early engagement between relevant services will need to take place. This will ensure suitability of proposed SuDs design in line with national standards. This service will be valuable to developers to help limit potential delays and reduce costs in the long term.

Full-applications must be submitted to the SAB for validation and must be 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

The SAB will have 7 weeks to determine applications other than those requiring an Environmental Impact Assessment, in which case it has 12 weeks. Application forms and adjoining documentation will be available from your local SAB and all submissions will need to be made to the relevant SAB.

How do I contact my SAB?

The start date for the approvals requirement is 7 January 2019 and our members are currently setting up their new service to deal with your applications and a dedicated webpage to provide you with additional information as it becomes available. Please contact us if you would like more information about this new process.


For more information contact: Jean-Francois Dulong


The Welsh Local Government Association (WLGA) represents the interests of local government and promotes local democracy in Wales.

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