How much water does the UK data centre industry consume? Nobody knows. Not the government, not the regulators, not the operators themselves. And the closer you look at the numbers being cited, the more that gap starts to look deliberate.

In August 2025, TechUK published what was positioned as the first comprehensive study of data centre water use in England. The headline findings were reassuring. 64% of surveyed facilities reported using less than 10,000 cubic metres of water per year. 51% said they had adopted waterless cooling. The conclusion: water consumption is primarily an American problem. UK data centres, the report implied, are clean and efficient.

The report surveyed 73 facilities. There are approximately 500 commercial data centres operating in England. Participation was voluntary and anonymous. Operators self-reported their own water usage. TechUK collected no data on facility size, power demand, or location. There was no independent verification.

TechUK itself acknowledged the “self-selection bias” built into the approach. Foxglove, the digital rights organisation, was less diplomatic, calling it “dodgy and misleading” with “methodological flaws we wouldn’t accept in an undergraduate essay.” Their own investigation estimated that existing UK data centres already consume at least 10 billion litres of water per year — a figure the TechUK report did not even attempt to calculate.

Decisions are being made on the basis of that gap.

What the actual numbers show

In April 2026, Global Action Plan published research showing that 84% of proposed UK data centres are sited in areas already classified as water stressed by the Environment Agency. Half of all planned facilities are clustered around London and the South East. Slough has 32 operational data centres with more in planning, including a 300MW gas-powered facility, in an area classified as “seriously water stressed.”

Thames Water’s own modelling estimates that under a high-growth scenario, data centres would drive almost 30% of all new water demand in the region — roughly 270 million litres per day. That is comparable to the daily water consumption of a city the size of Leeds.

The picture across the EU is similar. Around 30% of the population already lives in areas of permanent water stress. European data centre water consumption is projected to nearly double by 2031, from 0.93 trillion litres to 1.79 trillion litres annually. Spain, Greece, and Portugal have had consecutive drought years. They are also seeing a wave of hyperscale data centre proposals. (Hyperscale data centres are large-scale facilities housing 5,000+ servers, optimised for high-volume processing.)

So, on one side we have an industry lobbying group claiming UK facilities barely touch the water supply, based on a voluntary survey of 15% of the market. On the other we have planning data, utility projections, and independent research all pointing the other way. The sector has no mandatory reporting obligation that would settle it. No one is required to count.

Why nobody wants to know

The reason the measurement gap persists is geopolitical.

The UK and EU are racing to build domestic AI infrastructure. The urgency has nothing to do with water tables and everything to do with Washington and Beijing. Without sovereign compute capacity, European businesses and governments remain dependent on American hyperscalers and exposed to shifts in US trade policy. China, meanwhile, is building a parallel AI ecosystem beyond Western reach, and doing it with a structural energy advantage: surplus solar and battery manufacturing that the US and Europe simply do not have.

Brussels announced plans to triple EU data centre capacity within five to seven years. Westminster has designated data centres as Critical National Infrastructure. The EU’s Cloud and AI Development Act, expected in the first half of 2026, aims to streamline permitting and improve access to energy, water, and land for new builds. The political signal is: build fast, sort out the details later.

Better measurement would slow things down. If the sector had to report water consumption the way it reports energy usage, some of the sites currently in planning would face difficult questions. That is precisely why mandatory reporting keeps getting proposed and keeps not arriving.

Goldman Sachs told clients that 2026 commodity markets would be shaped by two forces: the US-China AI race and global energy supply constraints. Meanwhile, the best the UK’s National Drought Group could come up with was suggesting that citizens delete old digital photos and emails that are stored online to save water. Citizens. Deleting photos. While the government approves multi-hundred-megawatt gas-powered data centres in drought-risk areas.

The energy gap is worse

European data centre power demand is expected to grow by 150% over the next decade. The IEA projects installed generating capacity will grow by just 70%. That gap gets filled by renewables built at a pace Europe has not demonstrated, or by fossil fuel generation that undermines the carbon targets these same governments have set.

China has surplus solar and battery capacity. The US has abundant natural gas, though it faces an 80-gigawatt backlog of turbine orders stretching to 2029. Europe has neither.

So European grids are about to get dirtier. For any organisation running AI workloads, this is not abstract: the carbon intensity of your compute is tied to the grid it runs on. A workload that produces low emissions today may not next year, depending on where it runs and what the grid is burning to keep up.

Your provider won’t tell you this

Try asking your cloud provider for the carbon emissions attributable to your AI workloads. You will get uptime guarantees, latency metrics, cost breakdowns by the millisecond. Carbon? Water? You will receive silence, or estimates built on the same kind of self-reported, unverified data that the TechUK report was built on. Foxglove picked that apart in days.

If your organisation reports on scope 3 emissions — or will need to, under incoming EU regulation — “our cloud provider says it’s fine” is not a position that survives scrutiny.

The EU is drafting minimum standards for data centre water efficiency. The UK government has commissioned reports on mandatory water disclosure. When those requirements land, we think the split will be obvious: organisations with independent measurement will report real numbers, and everyone else will be scrambling to backfill data they never collected.

That is what we do at Tailpipe. We measure the carbon emissions of cloud and AI workloads using actual infrastructure data, not provider self-reporting. If your organisation needs to know the real environmental cost of its AI — not the version your provider would prefer you to see — talk to us.

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