Beckton desalination plant to restart by December after £500m spend
Thames Water confirms winter operation to refill reservoirs, though the plant has run only five times since 2011
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Thames Water will restart its Beckton desalination plant by the end of the year, the company confirmed on 14 August 2026. The plant, which turns seawater from the Thames estuary into drinking water, has run only five times since opening in 2011. It will now operate over winter to help refill reservoirs ahead of next summer.
The decision follows criticism of the plant’s limited use during droughts. Since 2011, it has supplied 7.2bn litres, enough for about seven days of London’s daily demand. The total cost has risen to £500m, paid for through customer bills. Thames Water supplies 16 million people across London and the Thames Valley.
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Winter operation planned despite past failures
A Thames Water spokesperson told *The Guardian* that preparations are underway at the Thames Gateway water treatment works in Beckton. The plant will only run if weather conditions, demand, and reservoir levels require it. The company has not confirmed how long it will operate or how much water it will produce.
The plant’s reliability has been questioned. Chris Weston, Thames Water’s chief executive, told MPs last year that the membranes used to filter salt from water were at the end of their life. The company struggled to replace them due to a lack of testing facilities. Weston called the plant a “big problem” and said it was “not a good investment”.
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High costs and political scrutiny
Operating the plant is expensive, largely due to electricity costs. Thames Water is already under financial pressure, with creditors effectively controlling the company for two years. The prime minister, Andy Burnham, will decide Thames Water’s future in the coming weeks. Burnham has criticised water companies for raising bills while failing to prevent droughts.
Thames Water was one of five companies allowed to increase bills over the next four years. Burnham said on 14 August 2026 that customers were not a “bottomless source of funding”. The Beckton plant’s winter operation could be more viable if wind power reduces electricity costs, but this remains uncertain.
What happens next
Thames Water will monitor reservoir levels and weather forecasts before deciding whether to run the plant. If it proceeds, the plant will operate from December 2026 onwards. The company has not set a target for water production or a timeline for resolving technical issues with the membranes.
Residents in Beckton and across London will see no immediate change in water supply. The plant’s output will depend on conditions, and any water produced will be stored in reservoirs for future use. Thames Water has not announced plans to replace the ageing membranes or improve the plant’s efficiency.
Questions this report answers
+How much has the Beckton desalination plant cost?
The total cost of the Beckton desalination plant is now £500m. This was funded through customer bills over 15 years, despite the plant running only five times since 2011. Critics argue the investment has delivered limited value.
+When will the Beckton plant start operating again?
Thames Water plans to restart the Beckton desalination plant by December 2026. The plant will operate over winter to help refill reservoirs, but only if weather conditions, demand, and reservoir levels require it.
+Why has the Beckton plant been used so little?
The Beckton desalination plant has run only five times since 2011 due to technical issues and high operating costs. Its membranes, which filter salt from water, are ageing and difficult to replace. The plant’s electricity costs also make it financially unattractive.
+Will the plant affect water bills in Barnet?
Thames Water was one of five companies allowed to raise bills over the next four years. The Beckton plant’s operation may not directly increase bills, but its £500m cost was funded by customers. The prime minister is reviewing the company’s future.
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