The project involves designing and building a 4.2-kilometer water tunnel using a tunnel boring machine to transport treated recycled water from Mogden Sewage Treatment Works to an outfall upstream of Teddington Weir. Additionally, a 150-meter-long, 2.2-meter-diameter tunnel will connect the River Thames to the existing Thames Lee Tunnel for water abstraction. These tunnels are designed to supply up to 75 million liters of water per day during drought conditions, utilizing water recycling technology.
“This scheme is a vital part of our strategy to secure sustainable water supplies for the future,” said a Thames Water spokesperson. “It will help ensure resilience against drought while incorporating advanced water recycling methods.”
The initiative is a key component of Thames Water’s Water Resource Management Plan, approved in 2024, which outlines strategies to secure water supply for the next 50 years. The project has also received funding approval from Ofwat under Thames Water’s 2025–30 business plan, with construction expected to begin in 2029, pending planning consent. The contract will follow the NEC4 Engineering and Construction Contract framework, with Stage One focusing on early contractor involvement during the planning and consent process. Stage Two will proceed upon approval and agreement on a target price within the budget.
“The Teddington project will enhance our ability to manage water resources efficiently,” said a Thames Water representative. “We are committed to delivering this project with high standards of sustainability and innovation.”
The scope of work includes construction design, ground movement analysis, mechanical and electrical installations, SCADA system integration, hydraulic modeling, enabling works, traffic management, and disposal of excavated material. A full commissioning phase will follow construction, with the system targeted to be operational by March 2033.
Bidders must submit responses to a procurement questionnaire, with selection based on technical expertise (70%) and cost (30%). The four highest-scoring applicants will be invited to tender, ensuring a competitive process to deliver this critical infrastructure project for west London’s water security.
