Behind Amazon’s industry-leading water efficiency score

As scrutiny of data center water consumption intensifies, Amazon is increasing its use of recycled water for cooling applications and running its servers at hotter temperatures to decrease its freshwater withdrawals.

Amazon Web Services withdrew 2.5 billion gallons of water for its data centers in 2025, the company disclosed on June 10. At the sites that it owns and operates, water withdrawals decreased by 2 percent from 2024 to 2025.

It’s the first time AWS has published its water withdrawal figures; the company has historically focused on its best practices for decreasing the freshwater needed for cooling, such as opting for recycled water in its chillers, running servers hotter and pulling in outside air. It expresses progress by tracking the liters of water used per kilowatt-hour of energy (l/kWh), a measure known as water usage effectiveness (WUE), which as developed 15 years ago by tech industry trade group Green Grid.

“Communities want increased transparency,” said Brandon Oyer, head of Americas power and water for AWS, referring to the decision to publish its water withdrawal data. “We still think efficiency is the metric to focus on. Efficiency is paramount to scaling a business.’

AWS data centers are already seven times more water-efficient than the industry average — using 0.12 l/kWh, the company reported.The industry average rating for WUE is 0.84 l/kWh.

For perspective, Amazon rival Microsoft achieved a WUE score of 0.27 l/kWh for fiscal year 2025; it withdrew approximately 2.7 billion gallons of water in 2024 (the 2025 figure isn’t yet available). Google hasn’t reported a WUE number publicly; it withdrew 9.9 billion gallons for its data centers and other operations, as of its latest environmental report in 2025.

Both Google’s and Microsoft’s totals include their entire operational footprint; Amazon’s figure is strictly for AWS.

‘Water positive’ mandates

All of the big data center companies — Amazon, Google and Microsoft — have pledged to be “water positive” by 2030. Meta, Facebook’s parent company, is also working on that goal. 

The tech industry downplays the water impacts of their IT infrastructure — data centers account for less than 1 percent of all industrial water use, or less than 1 percent of what Americans use to water their lawns. 

But their water pledges have become harder to satisfy amid the furious pace of data center expansion intended to support artificial intelligence services. The dilemma is compounded when you consider that about one-third of all energy needed for data centers goes toward cooling. “It’s a continuous balance,” said Oyer.

Another challenge is aging infrastructure at many water utilities. Amazon in March committed $235 million to upgrades in Oregon, aimed at addressing declining groundwater supplies. That’s just one of its investments.

Likewise, Google has so far committed more than $500 million toward water utility upgrades, including recycling systems. It has also pledged to opt for air cooling or recycled water in regions where freshwater sources are at “high risk.”  

AWS is prioritizing the use of reclaimed or recycled water in regions where water chillers are the most energy-efficient approach. It already supports 26 recycled water projects and has another 130 sites under contract. Using recycled water is also on the list of Google’s list of best practices. 

Water isn’t the only way to cool a data center: Many operators use chilly outside air pumped through the server halls to remove heat, although that’s only possible in certain regions. Liquid cooling technology also helps by dissipating heat at the chip level.

Amazon has also raised the temperature threshold for when chilling equipment switches on. The ambient temperature needs to exceed 85 degrees Fahrenheit before they’re used, reducing the number of hours per day that they’re in action. 

On one Amazon campus, this approach reduced water consumption by 50 percent compared with an identical data center configuration using a lower temperature to guide cooling.  

AWS is about 75 percent of the way to its water-positive goal. Aside from changing its chilling processes, it has so far supported more than 50 water replenishment projects — enough to return more than 5.8 billion gallons of water on an annual basis.

Neither Google or Microsoft has disclosed their progress toward becoming water positive on a percentage basis, but Google reported in early June that it has more than 165 projects under way that will replenish more than 19 billion gallons of water annually by 2030. 

Learn more about best practices for balancing water and energy during Trellis Impact 26, from June 23 to 25 in San Francisco.