The Teddington Direct River Abstraction (TDRA) project is a vital part of our long-term plan to secure water supplies for London. Over the last few years we’ve been going through a process of developing plans for the project, whilst carrying out extensive environmental surveys, public consultations and having detailed discussions with stakeholders. .

In 2025, we held a statutory public consultation on our proposals.  This was followed by a supplementary public consultation in May 2026 on proposed changes to our plans close to Burnell Avenue and Beaufort Road, and a targeted consultation in September 2026. Thank you to everyone who has taken the time to share their views. All the feedback we’ve received has helped shape our proposals. 

Water would be abstracted from the river upstream of Teddington Weir and transferred along a section of new connecting pipeline to an existing underground tunnel to our reservoirs to become drinking water.

The abstracted water would be replaced with recycled water from Mogden Sewage Treatment Works in Isleworth, transferred to the river along a new underground pipeline to an outfall structure upstream of Teddington Weir. This way, we’d be able to access additional supplies of water from the river, while ensuring river levels are maintained and the river environment and ecology protected.

Typically, wastewater is piped to sewage treatment works, where it can be filtered before undergoing “primary” and “secondary” treatment to make it safe to be released back into local watercourses. At some sewage treatment works there is a further stage, called “tertiary treatment", a process outlined in the image below.

We've completed testing water recycling processes in a pilot plant at Mogden Sewage Treatment Works.  We're working closely with the Environment Agency to consider the data from our testing, ensuring compliance with environmental safety regulations.

We’d only use the project during droughts, which we estimate will happen roughly every two years, usually between late summer and late autumn. We’d reach an operating agreement with the Environment Agency that would set out when we can use it. 

In order to keep the treatment facility in good working order at other times, we’d need to run water through it, at a low volume, called a “maintenance flow”. We'd release the “maintenance flow” of recycled water generated in standby mode into the tidal Thames at Isleworth Ait, through the existing Mogden Sewage Treatment Works outfall. Because it has been through the Tertiary Treatment Plant, the maintenance flow would support water quality improvements in that part of the tidal Thames.

In 2023, the Secretary of State confirmed that the project should be treated as a development of national significance for which a Development Consent Order (DCO) is required. Details of the Request and the Decision are available here. The DCO process provides opportunities for people to have their say on the proposals before a final decision is made by the Secretary of State. 

When we apply for permission to build the project in 2027, we’ll include a full Environmental Impact Assessment (EIA). This will set out how we we’d reduce and manage potential effects on the local community and surroundings during construction. We’d carefully manage things like traffic, noise, dust and lighting and would keep local people informed. We’ll continue to engage and work closely with organisations like the local authorities and Environment Agency as we develop the project further.