Thirsty data centres are sucking up Britain's scarce water supplies

Times

a day ago

Britain's data centres are consuming close to ten billion litres of water a year at least as the country braces for widespread drought, The Times can reveal.
Two regions are in drought, with more likely to follow, raising the possibility of summer hosepipe bans as rivers hit 'exceptionally' low levels, highlighting the squeeze on Britain's water supplies despite its rainy reputation. Yet there is no official estimate of how much water the nation's 450-plus data centres are using to keep their servers cool.
The chairman of the Environment Agency (EA) has warned that England is heading for a national shortfall of five billion litres of water a day by 2055, more than a third of the 14 billion litres a day used now. But that is without factoring in the rapid rise of thirsty generative AI tools, such as ChatGPT.
The British tech industry and the EA have been working in recent months to gauge water demand from data centres today and in years to come. Neither will publicly disclose a figure on data centres' water use.
However, figures released under transparency laws suggest that water companies are already supplying at least almost ten billion litres a year to 231 data centres, the equivalent of 3,980 Olympic swimming pools. The snapshot, obtained by the technology campaign group, Foxglove, and The Times, suggests Thames Water is far and away the biggest supplier of water to data centres.
About half of the UK's water companies were unable to provide figures to Foxglove, in part because data centres do not have to report their water usage. 'It is deeply alarming that over half our water companies have no clue how many data centres they supply, nor how much water they are hoovering up,' Donald Campbell, of Foxglove, said.
This information void exists as the government eyes data centres as a totemic part of its economic growth plans. Labour has said AI will 'turbocharge' growth, with £39 billion committed for more data centres in the next five to ten years.
Debate is also intensifying over the greater water demands of data centres running AI models. On June 10, Sam Altman, the OpenAI founder, mounted a defence of ChatGPT, saying an average user query required just one fifteenth of a teaspoon of water.
So, what is the truth? Is the growth in data centres and AI a threat to Britain's water supplies, at a time when climate change is already increasing the risk of droughts?
Most of the concern over data centres' environmental impact has focused on their energy use. Less understood is the impact of their water consumption. The Times's analysis has focused solely on water used directly for cooling the data centres themselves. While a small number are believed to use air cooling, most use water.
The most water efficient are 'closed loop' systems, while the thirstiest are 'open loop' ones.
The estimate of close to ten billion litres of water being used by about half of the UK's data centres is based on figures released under environmental information requests, The Times's conversations with individual water firms and, in the case of Thames Water, an unpublished report by the consultancy, Jacobs. The total is equivalent to the annual water use of 189,781 people, more than the population of Oxford.
The tally is almost certainly a large underestimate. It covers only about half of the data centres and the figures for Thames Water are three years old.
TechUK, the industry group, estimates there are 450 to 500 data centres in the UK. The group was unable to say what proportion uses each cooling technology. However, Luisa Cardani, TechUK's head of data centre programmes, said: 'Generally, you could argue that the newer data centres, especially when they are in water-constrained areas, will choose types of cooling like liquid cooling [closed loop] or direct to chip cooling [another approach] because it's more efficient.'
Britain's data centres are mostly running servers powering websites, cloud storage and the latest hit series on Netflix. However, servers running AI models are much more water intensive. A study last year found ChatGPT uses four times as much water as previously thought.
Some experts think the fears over water use are overwrought. Henry Shevlin, associate director at the University of Cambridge's Leverhulme Centre for the Future of Intelligence, noted most things of economic value consume water, from agriculture to football matches, and data centres running AI models are neither an exception or an outlier.
'Is the juice worth the squeeze? To the extent that we do care about economic growth, we should be prioritising economic and resource-intensive activity in areas that are also going to give us big payoffs. Obviously AI has phenomenal potential here,' Shevlin said.
Still, he said the tech industry should be more transparent about water use in Britain and the government could demand more openness. 'Revealing estimates of water usage and electricity usage are, let's be honest, they're not deep, sensitive corporate secrets,' he said. The result should be more water efficient data centres, Shevlin added. Anglian Water has even suggested data centres could be cooled with heavily treated effluent, known as recycled water, rather than water drawn from rivers and reservoirs.
Growth in AI is 'likely to result in a large and rapid increase in the number of data centres in England', the Environment Agency said on June 17. The concern, it said, is many will be built by 2030, before new reservoirs and water transfers are complete. Britain's first new reservoir in more than three decades, Havant Thicket near Portsmouth, will not be full until 2031, for example. 'It is therefore critical that water availability is considered early in the planning stage [of data centres'], EA officials said.
Angela Rayner, the deputy prime minister, has recently overruled local councils to give the green light for building new data centres, once at Iver in Buckinghamshire last December and this May for one at Abbots Langley in Hertfordshire. Water industry sources believe new data centres in the next five years could need the same amount of water as 500,000 people.
Thames Water said southeast England was already water-stressed and the region was earmarked for a large proportion of proposed new data centres.
'This brings a challenge between safeguarding our finite [water] resources while supporting the UK's growth strategy,' a Thames Water spokesman said. Water UK, the industry body, said: 'We need planning hurdles cleared so we can build reservoirs quickly'. An EA spokesman said: 'We are working with the technology sector to understand their needs, to help develop sustainable solutions.'
Campbell said: 'Water companies and the government are walking into this future with a blindfold on. Ministers and water companies need to wake up — the likes of Amazon, Microsoft and Google must not be given carte blanche to drain our rivers and streams.'