On 10th January 2023, DEFRA published a report of its review of sustainable drainage systems and announced plans to make SuDS mandatory for new developments in England. A consultation on the proposals is due to be carried out later this year with the intention to implement new requirements from 2024.

What is a sustainable drainage system?

SuDS collect surface water run-off and release it slowly, rather than discharging it all into the public sewer system or watercourse. In effect, SuDS mimic the way surface water run-off would have occurred had the land not been developed, which reduces the impact of flooding and pollution.

In Wales, SuDS have been mandatory since 2019 under Schedule 3 of the Flood and Water Management Act 2010, however in England SUDS are currently encouraged but are not mandatory.

What are DEFRA’s proposals?

DEFRA’s review recognised that there is an inconsistent approach under current planning policy in relation to the use of SuDS in England and they have recommended that Schedule 3 of the Flood and Water Management Act 2019 should be implemented in England.

What effect will implementation of Schedule 3 have?

DEFRA’s intention is that implementation will guarantee that SuDS are designed, constructed, adopted and maintained to national standards throughout the development’s lifetime. Details of the scope, threshold and process will follow once the government have carried out their consultation.

The proposal is that a SuDS Approving Body (SAB) will sit within the unitary authority or county council and the net additional cost to local authorities to set up the SAB will be assessed and funded by central government, however it is expected that once the SAB has been formed, the operational costs of the SAB will be covered by developers paying application and inspection fees as part of their application process.

Under Schedule 3 (as implemented in Wales) there are already some developments which are exempt from SAB approval such as development under 100 square metres, single buildings under 100 square metres and construction work carried out by an internal drainage board will not require approval and these exemptions will be reviewed as part of the consultation process.

For developments at an ‘advanced stage of planning’ at the point in which the new legislation is implemented, there will be transitional arrangements in order to avoid incurring additional work and costs. The details of what constitutes an advanced stage of planning are not yet known, but developers are advised to keep appraised of the consultation during the planning and development process.