Sustainable Drainage Systems (SuDS)

Sustainable drainage systems (SuDS) refer to a range of environmentally friendly rainwater management techniques, such as soakaways, to reduce water run-off entering sewers and to prevent flooding. They manage surface water in a way that mimics natural processes, providing benefits that traditional drainage methods do not (for example, use of nature-based SuDS to support biodiversity).

Schedule 3 of the Flood and Water Management Act 2010 requires all new developments to incorporate SuDS to manage runoff water effectively. Schedule 3 is in force in Wales but is not in force in England.

However, the government made changes to its National Planning Policy Framework (NPPF) to support increased delivery of SuDs in 2024. The NPPF is the government’s national planning policy for England, it is non-statutory and is treated as a material consideration in planning decisions – however, it does not mandate SuDs for new developments. The government also introduced non-statutory guidance on National Standards for SuDS in England in 2025.

The government has also said that it is “strongly committed to improving the implementation of SuDS” but that better delivery of SuDS may be achieved through improving planning policy, as well as adoption and maintenance, rather than through bringing schedule 3 into force in England. The government said that a final decision on commencing schedule 3 “will be made in due course”.

Stakeholders are generally positive about the benefits that SuDS can provide, and many have called for SuDS to be made mandatory for new developments. However, there are more nuanced opinions about the way in which SuDS should be delivered. Some have called for schedule 3 to be implemented, while others have expressed challenges around the planning and approval process that would be required.