Defra publishes national standards for sustainable drainage systems
The Department for Environment, Food and Rural Affairs (Defra) has published non-statutory standards for the design, maintenance and operation of sustainable drainage systems (SuDS) in England. These standards apply to new infrastructure and development on both greenfield and brownfield sites, excluding retrofit projects and the trunk road network managed by National Highways. The guidance sets out seven standards that address runoff destinations, the management of both everyday and extreme rainfall and flooding, water quality, amenity, biodiversity, and the design, construction, operation, maintenance, decommissioning and structural integrity of SuDS. SuDS are designed to manage surface water in a way that replicates natural processes, delivering benefits such as water reuse; reduced flood risk through runoff storage; and improved water quality through pollutant filtration, among other aspects. The standards are aimed at designers, property developers, local authorities and other key stakeholders, including sewerage undertakers and the Environment Agency.