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Cardiff Council

Sustainable Drainage Systems (SuDS)

​​​​​​​Traditional drainage systems can increase the risk of flooding and pose a serious risk of contamination. Sustainable Drainage Systems (SuDS) have been developed to imitate the natural drainage process and eliminate these risks.

This is in order to maintain the quality and limit the total amount of water leaving a site.

SuDS aim to provide the community with green spaces promoting diverse wildlife and wellbeing. Watch the video for more information on ​the benefits of SuDS.   

Video id: LMq6FYiF1mo
From January 7th 2019, all new developments 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 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.

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 will be published by Welsh Government in the autumn but in the meantime, we recommend that you refer to the Statutory Ministerial National Standards​​​​​​​​​​​​​​​​​​​​​​External link opens in a new window and the CIRIA 753: The SuDS Manual​​​​​.​​​​​​​​​​​​​​External link opens in a new window

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 the Schedule 3 of the Flood and Water Management Act 2010.​​​​​​​​​​​​​​​​​External link opens in a new window
The SAB is a statutory function delivered by the local authority to ensure that drainage proposals for all new developments where the construction area is 100m2 or more 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.
Whether you are a developer, an agent or an individual seeking planning permission for a development, if your development is 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 that 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 that covers an area of land of less than 100m2, is excepted from the requirement for 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 will be separate from the planning pre-application service so early engagement between yourself and relevant services will need to take. This will ensure suitability of proposed SuDS design in line with national standards and adequate site layout. This service will be valuable to developers to help limit 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, and
  • 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.

Find out how to apply for SuDS.​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Link opens in a new window
The start date for the approvals requirement is 7 January 2019 and we are currently setting up our new service to deal with your applications and a dedicated webpage to provide you with additional information as it becomes available.

If you would like more information about this new process, please contact us on​​​​​​​​​​​​​​​​​​​​​External link opens in a new window

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


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