Britain’s only desalination plant remains idle during drought
Water flow in the river Thames has dropped low enough to warrant the use of England’s only large-scale desalination plant, but it hasn’t been switched on at all this year
Water levels on the river Thames in London have dropped low enough to allow the production of drinking water from mainland Britain’s only desalination plant – but it is currently out of service.
The £250 million Thames Gateway desalination plant in Beckton, east London, opened in 2010 and remains mainland Britain’s only large-scale desalination plant. It was designed to provide additional drinking water to the capital during times of severe drought by turning brackish water from the Thames into potable water.
But despite the UK recording its driest July since records began in 1836 and suffering what government officials have described as an “exceptionally serious” drought, the plant has not been used at all this year.
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Under Thames Water’s drought plan, the firm is allowed to start using its desalination plant if a drought is declared and if water flow rates in the Thames drop below 3000 megalitres per day (Ml/d).
A drought was declared in England on 29 July 2026, and data obtained by New Scientist suggests water flow rates at Teddington in south-west London, the lowest point of the freshwater Thames, have been well below the 3000 Ml/d mark for weeks.
In fact, the current rates are around 220 Ml/d, below even the target river flow threshold for Teddington of 300 Ml/d agreed by Thames Water and the Environment Agency during the current drought. Normally, the target flow rate for the river is 800 Ml/d, to protect the river’s ecology and surrounding environment from over-abstraction by Thames Water.
Under normal circumstances, the current situation would allow Thames Water to start producing drinking water from the Beckton plant, to relieve pressure on other water sources. The Thames Gateway plant is capable of providing up to 100 Ml/d of water, about 4 per cent of the daily volume of drinking water supplied by Thames Water.
But the desalination plant has been beset with technical problems and is currently out of supply, according to Thames Water. Its 2027 draft drought plan published earlier this year reports that work is under way to replace damaged equipment, including the plant’s membranes, which act as filters for fresh water.
The plant has only ever run five times, reporting last year revealed, delivering the equivalent of seven days’ worth of drinking water supplies to London. It has not been used at all this year, despite the worsening drought. Thames Water’s drought plan suggests the plant would take four to six weeks to ramp up to full capacity.
A spokesperson for Thames Water said the firm was working to ready the plant for operations later this year. They said in a statement: “Preparations are under way at the Thames Gateway Water Treatment Works in Beckton East London so it can be brought online by the end of the year, if needed, to help support reservoir recovery over the winter. Any decision to use the desalination plant will depend on weather conditions, demand, and reservoir levels in the coming weeks.”
Data released by the Environment Agency this month confirmed that July 2026 was the driest July for the Thames area since records began in 1871, with the region receiving just 1 millimetre of rainfall for the entire month. Parts of the river Thames are suffering exceptionally low flows, which can lead to low oxygen levels and deteoriating river health.
The problems at the Beckton desalination plant come as other water companies look to build desalination plants across England, in a bid to shore up water supplies as climate change brings more frequent and intense droughts to the country.
Anglian Water is developing plans for two plants in Norfolk and Lincolnshire, using seawater from the North Sea. Meanwhile, South West Water is also drawing up plans for a desalination plant in Par, Cornwall, to help the county cope with the increased water demands during the busy summer months.
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