Thames Water has unveiled a drought resilience project to supply West London, as it warns climate change could create shortages by 2050.
The UK’s largest water company is developing measures to supply up to 75 million litres a day to the region using water recycling, describing the South East as “seriously water-stressed”.
Figures taken between 2021-25 show a sharper contrast between the company’s Lower Thames and Lee reservoir groups when compared with previous data since 1989, when Thames Water acquired the reservoirs upon privatisation.
In these recent years, the Lower Thames reservoirs has consistently held a lower proportion of usable water than the Lower Lees groups.
Thames Water explained its West London reservoirs are filled from the River Thames, meaning higher river flows allow more water to be stored.
But its resilience plans raise questions about what water stress means in practice for London, especially how close the region might be to the limits of its current supply.
A spokesperson said: “Climate change, combined with population growth and the need to reduce our impact on the environment, means there will be a shortfall in water supply by 2050 if we don’t take action now.
“The Environment Agency designated the South East as seriously water stressed and forecasts more frequent droughts.
“It’s why we’re planning ahead to meet future demand and ensure long-term water resilience.”
As of March 11, Thames Water said its reservoirs were 92% full in West London and 96% in the Lee Valley.
The company said Thames flows are sustained by groundwater baseflow, largely from the Chalk aquifer upstream which is typically replenished by wet winters.
River flows drop with groundwater levels, increasing pressure on storage and demand management during hotter, drier periods.
In response to the “seriously water-stressed” designation for the South East, Thames Water is also developing plans for a major new reservoir in Oxfordshire.
The company said the proposed White Horse Reservoir near Abingdon, put forward for public consultation in October 2025, would supply Thames Water as well as Affinity Water and Southern Water.
During drier periods, it said water would be released from the reservoir back to the River Thames through a new structure.
The spokesperson said: “Water would flow downstream to existing treatment works in London, ready to supply homes and businesses.”
“The reservoir would also supply people locally in Oxfordshire and water customers in Hampshire.”
Featured image by Marc Kandalaft on Unsplash
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