Building and Developing

Sustainable Drainage on new developments in Wales

How we manage surface water will change from January 2019

The Welsh Government has introduced new legislation, Schedule 3 of the Flood and Water Management Act 2010, that will come into force on 7th January 2019.

The purpose of this legislation is to ensure that Sustainable Urban Drainage Systems(SuDS) are considered and used to manage surface water; ensuring resilient drainage systems for new developments in both urban and rural areas.

This means that from this date onwards the following will apply:

  • All new developments of more than 1 house or where the construction area is 100m2 or more, will require sustainable drainage systems (SuDS) for managing surface water.
  • Drainage systems for all new developments must be designed and built in accordance with statutory SuDS standards.
  • The destination of the surface water and the method of removal / management is a key consideration. Designs must comply with the differing surface water destination priorities contained within the Welsh Government’s standards.
  • Local authorities will become the SuDS Approving Body (SAB).
  • SuDS schemes must be approved by the local authority acting in its SAB role before construction work begins.
  • The SAB will have a duty to adopt compliant SuDS so long as it is built and functions in accordance with the approved proposals, including any SAB conditions of approval. 

Our role will change as a result The SAB will be the approving body for SuDS designs and also the adopting and maintaining body for the new surface water network in many cases. This includes both the SuDS features and the connecting drainage networks which we traditionally adopted. Therefore when your development requires SAB consent, Hafren Dyfrdwy will no longer be the default adopting authority for surface water drainage in Wales.

The Welsh Minsters mandatory standards for gravity foul sewers and lateral drains, and mandatory adoption provisions will not change the introduction of Schedule 3. The requirement to secure our consent to connect surface water to the public sewer network is still required, but SAB approval must be in place first.

The Design Guide ‘Sewers for Adoption 8th Edition’ will not be applicable across our operational area.

Our adoption policy with our English operational areas will not change. Mandatory sewer adoption provisions will remain and we will continue to adopt surface water sewers which must be designed in accordance with Sewers for Adoption 7th Edition. 

Transitional arrangements

The requirement for SAB approval and adoption agreements for surface water drainage is not retrospective. It only applies to new developments.

Existing sites and developments with planning permission granted or deemed to be granted (unless subject to reserved matters – see below), or where a valid application had been received but not determined by 7th January 2019, will not be required to apply for SAB approval.

SAB approval will 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 7th January 2020.

When SAB approval is not required

  • Developments with drainage implications of a single house and the area of land covered by the construction work is less than 100m2 , or
  • In the case of any other type of construction work, the area of land covered is less than 100m2.

Subject to the exemptions from the need for SAB approval, the SAB approves but does not adopt SuDS if the scheme:

  • Serves a single property.
  • Is a publically maintained road (where section 41 of the Highways Act 1980 applies)
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