Water UK: government AI datacentre plans ignore water supply

The UK's water industry has picked a fight with the government's AI growth story, and it is worth reading the fight on its own terms rather than as background noise. In a written briefing to MPs, Water UK, the trade body for water companies in Britain and Northern Ireland, said the government's water forecasts are 'fatally flawed' because they 'explicitly exclude' datacentres from the demand modelling, as reported by The Guardian. Jon Chappel, the body's deputy director, called that omission 'unforgivable' and a 'genuine failing of government'.

The numbers Water UK put in front of MPs are the interesting part. Datacentres in England currently draw roughly 6.6 million litres of drinking water a day. If the government hits its stated ambition to triple datacentre capacity by 2030, that rises to about 19.8 million litres a day. Set against that, England is already running 220 million litres a day short of what water forecasts assumed, with a projected 5 billion litre daily shortfall by 2055. More than three-quarters of UK datacentres sit in the south and east of England, the same regions where hosepipe bans are now a regular summer feature.

What makes this politically awkward is where datacentres sit in the pecking order. They are designated critical national infrastructure, which in a genuine drought could put server halls ahead of households for supply. Water UK also notes that the government's AI growth zones policy, its AI for science strategy and its AI opportunities action plan 'make not a single mention of water', a gap campaigners at Global Action Plan have been pushing on for months.

The honest caveat is that a lot of the modelling here is contested. Individual datacentres are reportedly requesting up to 3 million litres a day, but consumption varies enormously between evaporative and closed-loop cooling designs, and the reporting does not break the 19.8 million litre projection down by cooling type. Nor does it tell you whether the government's promised nine new reservoirs will actually land in the same water-stressed regions where the compute wants to be built, or on what timeline.

The forward-looking bit for anyone building or buying UK compute: water is about to become a permitting variable that sits next to grid capacity, not behind it. Operators who can credibly point to closed-loop cooling, or to sites outside the southeast, are about to have a much easier sales conversation than the ones who cannot.