ENERGY AND WATER
Estimates for the water behind one AI query differ by a thousandfold.
The thousandfold spread
All of these are real, published, and about "an AI query". They disagree because they are answering different questions.
What changes between them: whether electricity generation is counted, how long the output is, which hardware generation, and which facility in which climate. None of those are details — each one moves the answer by an order of magnitude. A per-query water figure quoted without its method is close to meaningless, and that applies to the reassuring numbers as much as the alarming ones.
A US national laboratory analysis found American data centres consumed roughly 66 billion litres directly for cooling in 2023 — while the electricity powering them accounted for approximately 800 billion litres indirectly. The indirect footprint is more than ten times the direct one. Which means a facility that switches to air cooling and announces near-zero water use has addressed the smaller share. Only changing the power source addresses both.Lawrence Berkeley National Laboratory, United States Data Center Energy Usage Report, December 2024
What the operators themselves disclose
These are the firmest numbers on the page, because companies reporting their own rising consumption have no incentive to overstate it.
- Google: 10.9 billion gallons in 2025 — a 34% year-on-year rise and more than double its 2021 figure, the steepest single-year increase in its disclosed history.Google 2026 Environmental Report
- Amazon: 2.5 billion gallons in 2025 — the company's first water disclosure.
- Microsoft: 0.30 litres per kilowatt-hour fleet-wide, and piloting cooling designs that avoid evaporation entirely, which it estimates saves around 125 million litres per data centre annually.
Worth noting what these disclosures have in common: they are recent, inconsistent in method, and in Amazon's case first-ever. The transparency is newer than the problem.
Where it is drawn matters more than how much
Water consumed by evaporation does not return to the source, so local scarcity — not global totals — determines the actual impact. The same volume means something very different in a wet region than in one rationing supply.
An analysis of data centres built since 2022 found roughly two-thirds located in water-stressed regions, and a review of some 14,000 data centre assets concluded about one in four may face increased water scarcity by 2050. Some of the largest expansion zones sit inside areas already under long-term drought — which is why one operator is piloting its zero-evaporation cooling in exactly such a region.Bloomberg News analysis of siting since 2022; MSCI review of ~14,000 data centre assets, 2025
The energy side, briefly
The energy figures are firmer than the water ones. The International Energy Agency projected global datacentre electricity demand roughly doubling by 2030 to around 945 terawatt-hours in its April 2025 Energy and AI report — just under 3% of world electricity demand, against about 415 TWh consumed in 2024 — and has since updated that central projection to about 950 TWh. The agency's own comparison: a large data centre can consume as much electricity as 100,000 households, and the largest under construction as much as 2 million.IEA, Energy and AI, April 2025, Base Case; central projection subsequently updated. Full treatment in the Forge.
Ask four questions before repeating a number. Direct or total? (the indirect share is ten times larger) · Consumption or withdrawal? (only consumed water is lost to the basin) · Which hardware, which year? (efficiency has moved fast) · Where? (the same litres are trivial in one basin and contested in another). A figure that cannot answer all four is not evidence, whichever direction it points.
Both the alarmed and the dismissive positions are being argued with unusable numbers. "Every email you send boils a bottle of water" drops the conditions that produced it; "a query uses a third of a millilitre" quietly omits the electricity that made it possible. The defensible position is narrower: consumption is rising fast and is now disclosed, the indirect footprint dominates the direct one, and siting decisions matter more than totals. That is less satisfying than a slogan, and it is what the evidence supports.