Datacentres in water-stressed south-east threaten household supplies, trade body says

The UK will not possess sufficient water supplies to accommodate the burgeoning datacentre industry underpinning the government's artificial intelligence ambitions, the water industry has warned in a stinging critique of official planning assumptions that campaigners say could ultimately pit household consumers against the digital economy. Water UK, the trade body representing water companies across Britain and Northern Ireland, has told MPs in a publicly available written briefing that the government's water forecasts are "fatally flawed" and "explicitly exclude" datacentres, despite the vast quantities of water required to cool the densely packed servers that power the AI revolution through cooling towers, chillers and humidification systems, alongside the substantial indirect consumption associated with high electrical power demands. The organisation noted that the government "makes not a single mention of water" in its policy for delivering AI growth zones, its AI for science strategy or its AI opportunities action plan, while the Environment Agency's most recent national framework for water resources, published in June 2025, also failed to include any estimate of datacentre water requirements.

"There appears to be an assumption that the country will always have enough water for its economic needs," the briefing said, adding that "nothing could be further from the truth" – a warning that carries particular urgency given that a House of Lords report in May concluded that England faced a 5 billion litre a day shortfall for public water supplies by 2055. Water UK said datacentres were already being built in water-stressed areas, with more than three-quarters located in the south and east of England, regions where millions of people have been placed under hosepipe bans by water companies following prolonged extreme heat and lack of rainfall. The trade body cautioned that any new datacentre growth in these areas "may be impossible" without policy change because of existing pressure on the network, noting that leakage and demand targets were already "very ambitious" and that the only solutions to deliver new supply – increasing water taken from the environment, which may be harmful, or building new supplies such as reservoirs – faced significant obstacles.

"Major reservoirs can take 15 years to plan and build," Water UK wrote, while acknowledging that water companies had cut leakage by around 40 per cent since privatisation and planned to reduce it by a further 17 per cent by 2030. Greenpeace, however, said last week that water companies were wasting five times more water through leaky pipes than even a national hosepipe ban would save, highlighting the scale of the challenge facing the industry. The concentration of datacentres is particularly acute in Slough, served by Affinity Water, where approximately 125 datacentres are proposed or under construction in a region much of which is subject to a hosepipe ban; the company told MPs in May that some of these facilities were requesting up to 3 million litres of water a day, equivalent to the peak water demand of 3,500 homes.

"The planning framework is built around household growth and per-capita consumption, and has not adapted to commercial users whose water needs can match those of a market town," Affinity said in a written submission to the environmental audit select committee, underscoring the regulatory gap that has allowed datacentre water demands to escape scrutiny. Because of Environment Agency permitting, datacentres are currently required to make use of drinking water only, with Water UK estimating that datacentres in England use 6.6 million litres of drinking water every day – a figure that could increase to 19.8 million litres a day if the government achieves its ambition to triple datacentre capacity by 2030. Jon Chappel, Water UK's deputy director, described this as "unforgivable" and a "genuine failing of government", while noting that England's current water shortfall was 220 million litres more a day than had been assumed in forecasts, a deficit currently being met by "accepting a greater risk of environmental harm, and restrictions on water use in the event of drought".

Similar concerns have been raised in Ireland, where hosepipe bans have ignited criticism of water companies and the government over a lack of clarity about datacentres' water usage, reflecting a wider European pattern of tension between digital infrastructure and water resources. The government has designated datacentres as critical national infrastructure, on the basis that their loss or compromise could result in "major detrimental impact on the availability, integrity or delivery of essential services" and "significant impact on national security, national defence, or the functioning of the state" – a status that Oliver Hayes, head of big tech and campaigns at Global Action Plan, said could leave water companies powerless to restrict their water use. "I think it is highly likely that we're going to end up seeing datacentres that are actually running chatbots, or enabling people to do benign and very wasteful, pointless things, protected and given favourable treatment when it comes to resources," Hayes said, warning of the risk that datacentres could be prioritised over households at times of peak water demand.

Chappel said Water UK had asked the government to publish a drought hierarchy to set out which sectors are prioritised in times of water shortages, but that ministers had yet to do so, adding that "without this there will be a trade-off across society". The concerns have been amplified by a £75 million campaign announced at the end of June by water companies, Ofwat, the Environment Agency, the Met Office and Natural Resources Wales to encourage people to use less water, even as water use per person in England and Wales remains among the highest in Europe. The government was expected to publish a national policy statement for AI growth in February, providing an overarching strategy and defining how cumulative impacts are considered, but this has been delayed, leaving the water industry and environmental campaigners in limbo. A government spokesperson said: "The environment and sustainable development must go hand-in-hand and we will protect our water supply while unlocking growth, including looking at alternatives or ways to minimise impact on supplies and output of wastewater from datacentres," adding that ministers were taking "decisive measures to secure water supplies and meet higher demand, including record levels of infrastructure investment and building nine new reservoirs."