What Is SuDS?
An introduction to Sustainable Drainage Systems — how they work, benefits, and UK requirements.
Last updated: 2026-03-26
Sustainable Drainage Systems (SuDS)
SuDS manage surface water runoff in a way that mimics natural drainage. Instead of piping rainwater directly into sewers and rivers, SuDS slow it down, clean it, and allow it to soak into the ground.
The Four Pillars of SuDS
- Water Quantity: Reducing the rate and volume of runoff
- Water Quality: Removing pollutants before water reaches watercourses
- Amenity: Creating attractive blue-green spaces
- Biodiversity: Supporting wildlife with wetlands and green corridors
Common SuDS Techniques
- Rain gardens: Planted depressions that collect and filter runoff
- Permeable paving: Allows water to soak through the surface
- Swales: Shallow, vegetated channels that convey and filter water
- Attenuation basins: Areas that temporarily store excess water
- Green roofs: Vegetated roofs that absorb rainfall
- Soakaways: Underground chambers that allow water to infiltrate
UK SuDS Requirements
Schedule 3 of the Flood and Water Management Act 2010 is being implemented, making SuDS approval mandatory for new developments. Most planning authorities already require SuDS as a condition of planning permission for major developments.