Sustainable Drainage Systems
Sustainable drainage systems (SuDS) provide an alternative to directly channelling surface water through sewers or to nearby watercourses.
They replicate natural drainage by managing rainfall close to where it falls using infiltration or attenuation (reducing the flow). This helps to manage flood risk and water quality, and can also provide amenity benefits and habitats for plants and animals.
The need for alternative drainage, such as SuDS, is needed to help meet environmental challenges such as climate change and population growth.
Water companies in England have implemented the sewerage sector guidance as a requirement of Ofwat's Adoption Code in April 2020. A major change in the new guidance is that, for the first time, guidance on the type of SuDS that will be adoptable is provided.
SuDS are always site specific, and require bespoke design that take into account the underlying hydrology and functional purposes of the area being developed. Provision for SuDS and the national standards required for their design, construction, maintenance, operation and adoption is included in the new Design & Construction Guidance and CIRIA SuDS manual. To compliment the industry guidance we have also produced some supporting guidance for common adoptable SuDS features as well as landscaping and planting advice and some FAQ’s, our sample technical assessment sheets also clarify the documentation and design checks required when incorporating SuDS into an adoptable solution. Please see our SuDS technical library below.
If your development proposal does incorporate any SuDS component which interact with an adoptable system, contact should be made with our technical team at your earliest convenience, please complete the Section 104 pre-application form and include as much relevant detail as you can. These discussions can help prevent delays later in the pre development process.
We continue to work with the Local Authorities to promote the use of SuDS on all new developments, and options for SuDS must be explored in accordance with planning practice guidance.
Further information on SuDS is available on the susdrain website.
SuDs technical library
SuDS Adoption Policy
S104 SuDS Guidance documents
- S104 Basin Guidance (PDF 844 KB)
- S104 Pond Guidance (PDF 1,362 KB)
- S104 Swale Guidance (PDF 1,471 KB)
- SuDS inlet, headwall & forebay details (PDF 3,240 KB)
- S104 Bio-retention Guidance (PDF 378 KB)
- S104 Filter Drain Guidance (PDF 406 KB)
Sample S104 technical appraisal forms
- Basin (PDF 407 KB)
- Pond (PDF 470 KB)
- Swale (PDF 405 KB)
- Bio-retention (PDF 363 KB)
- Filter Drain (PDF 358 KB)
- Infiltration viability (PDF 288 KB)
- Geocellular Infiltration (PDF 355 KB)