Section 104 Agreements: Getting Your Sewers Adopted
Section 104 Agreements: How to Hand Over Your Drains to the Water Company
For developers, the long-term maintenance of drainage is often an unwanted liability. The goal is usually to have the new sewers “adopted” by the local Water Authority (e.g., Thames Water, Severn Trent, Anglian Water). This process is governed by Section 104 of the Water Industry Act.
What is a Section 104 (S104) Agreement? It is a legal agreement between the Developer and the Water Company. It states that if sewers are built to specific standards (Design and Construction Guidance – DCG), the Water Company will take ownership of them once the build is complete.
Why Do You Need It?
- Release of Bond: Typically, a bond (cash surety) must be paid to the Water Company. This is generally not returned until adoption is signed off.
- Property Sales: Solicitors for new home buyers will check if an S104 agreement is in place. If not, they may advise their clients not to complete the purchase, fearing future maintenance costs.
Common Pitfalls The standards for adoptable sewers are higher than private drains. Manholes must be specific sizes, and gradients must ensure “self-cleansing” velocity. Since 2020, Water Companies can also adopt certain SuDS features (like basins), provided they meet strict criteria.
Civil engineers assist with the S104 process by producing the technical drawings and hydraulic calculations required to facilitate the technical approval process efficiently.
Disclaimer: The information provided in these articles is for general interest and educational purposes only and does not constitute professional structural engineering advice. Every project is unique. You should always consult a qualified Structural Engineer for site-specific advice before undertaking any construction work.
