Sam Altman, chief executive of OpenAI, has called community concerns about AI data centres consuming water “insane”. Scientists who study the question are less certain about almost everything else.
Why AI data centres are facing backlash worldwide as communities raise concerns over water use, electricity demand etc (Pexel/Representative image) (Pexel) “We don’t have the real ground-truth numbers on data-centre water use to put everyone on the same page,” Eric Masanet, a sustainability researcher at the University of California, Santa Barbara, told The Atlantic.
This is the central problem. As AI drives expansion of server infrastructure, freshwater costs are substantial, contested and largely unknown.
How data centres consume water Amazon’s disclosure last month that its data centres consumed 2.5 billion gallons (about 9.5 billion litres) of water in 2025 — roughly 5% of Seattle’s annual consumption — was among the most detailed public accounting any major cloud company has produced.
Still, the figure excluded all water consumed by power plants generating its electricity, Bloomberg reported. That omission can be consequential.
The International Energy Agency (IEA) estimates that about two-thirds of all water used by data centres is linked to electricity generation, and about one-fourth tied to on-site cooling, according to a peer-reviewed commentary published in AGU Advances in January 2026 by researchers Ana Pinheiro Privette, Ana Barros and Ximing Cai of the University of Illinois Urbana-Champaign.
AI companies rely on primarily two options for cooling – evaporative towers, which use water evaporation to lower air temperature, and closed-loop cooling, where water circulates in sealed systems rather than evaporating.
Closed-loop cooling eliminates direct water loss, but it comes at an energy cost because these systems require a lot more electricity than the alternative evaporative towers, The Atlantic reported.
Since generating electricity is itself water-intensive, demand is displaced rather than removed.
Another parameter reported by companies is water-use efficiency, which is essentially the ratio of water usage to energy consumed.
Also read: New York becomes first US state to freeze large data center construction over rising power costs and water use concerns
Amazon reported a water-use efficiency of 0.12 litres per kWh in 2025, down from 0.15 litres in 2024. By its own account, Microsoft’s figure was 0.27 litres in its most recently reported fiscal year.
The broader industry average stands at around 0.84 litres per kWh, according to Amazon Web Services, which adjusted an academic estimate to produce the figure.
But even these comparisons may not be level. Amazon’s metric, Bloomberg reported, includes discharged wastewater, which most competitors exclude.
Fundamentally, water usage effectiveness is tracked by fewer than one-third of data centre operators, the commentary published in AGU Advances said.
Fighting the farms The expansion of data centres, driven by the AI boom, has stirred up opposition.
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