Step forward for new reservoir serving the South East
Following on from an important publication in the development of a major new reservoir project for the South East, our Major Projects Director Ben Ring shared his thoughts.
On the morning of Thursday 14 August 2025, colleagues at Thames Water published the ‘Gate Three report for SESRO’
It’s great to see that progress continues to be made with the new South East Strategic Reservoir Option (SESRO) project in Oxfordshire.
This latest update has been submitted to the joint regulatory body RAPID – marking another important milestone in the development of this key piece of national infrastructure.
When complete in around 2040, the 150-billion-litre reservoir will be able to supply about 270 million litres of water a day to 15 million people across the South East – including Southern Water customers.
Water from the reservoir would be brought into Hampshire by our planned Thames to Southern Transfer project, which last month was classed as a Nationally Significant Infrastructure Project by the Government.
The 80-85km transfer pipeline will be capable of transporting up to 120 million litres of water a day into Hampshire – reducing our reliance on the environment to provide water, especially during a drought.
The transfer is one of a number of new sources of water we are creating to help protect Hampshire’s Test and Itchen rivers – two of the world’s finest chalk streams - and provide a safe, reliable supply of water for hundreds of thousands of people for generations to come.
Now we have reached this milestone, we are creating a dedicated webpage to share developments with our customers - but in the meantime, all the information you need can be found online here.