Key takeaways
- Amazon's data centres are over 7x more water-efficient than the industry average, using air cooling for most of the year and water only during the hottest days.
- We're 75% of the way to our goal of being water positive by 2030, meaning that for every litre of water we use in our data centre operations, we will return more than a litre back to the communities where we operate. In 2025, we returned 3 litres for every 4 we used — and we've announced over 50 water projects that are expected to return more than 22 billion litres annually once fully implemented.
- We use reclaimed water (water that would have otherwise been wasted or unusable) across more buildings than any other company, and we're helping communities develop reclaimed water programmes from the ground up.
When data centres use water for cooling, one of the most important metrics is how efficiently they use that water — meaning how little water they use for each unit of compute. Amazon today announced that its global data centre operations used just 0.12 litres of water per kilowatt-hour (L/kWh) in 2025, a rate that's over 7x more efficient than the industry average of 0.84 L/kWh.
In other words, we use far less water per unit of compute than others in the global data centre industry, which as a whole accounts for less than 0.5% of all industrial water use globally.
And we're continuing to get even more efficient year-on-year. These efficiency gains are the result of years of investment in custom cooling technology, smarter systems, and a commitment to minimise water use wherever possible.
How Amazon cools its data centres
"Data centres enable everything from video calls to virtual medical visits and education to online banking," says Joern Tinnemeyer, a data centre engineering leader at Amazon. "To deliver that computing reliably, we need to maintain optimal temperatures. My team focuses on thermal management — taking the heat generated as a byproduct of computing operations and removing it as effectively and as efficiently as possible."
About 90% of the time, our data centres use "free air cooling," pulling in outside air, running it past servers to absorb the heat, then pumping it back outside — no water involved. In Europe, where temperatures are moderate for much of the year, this proportion is even higher. "It's kind of like in your house," Tinnemeyer says. "It's a nice summer morning. It's not that hot out. I'm going to open up my windows rather than turn the air conditioner on, and just let the breeze pull through."
But when the hottest hours of the hottest days arrive, especially in warmer parts of Europe, the air gets too hot and humid to cool the servers effectively. This is when we use evaporative cooling, in which water is sprayed onto an absorbent medium that Amazon water specialist Beau Schilz describes as "a sophisticated, giant sponge." Hot air flows through this water-soaked material, and as the water evaporates, it pulls heat from the air, cooling it by 3 to 6 degrees Celsius.
"It's like sweating," Schilz explains. "The evaporative process pulls the heat off of your body so you don't overheat."
Some companies instead use chillers that work like giant air conditioners. But with currently available technology, using water during hot hours actually reduces overall environmental and community impact. That's because chillers typically require 25% to 35% more electricity, and that extra demand often comes precisely when everyone else needs power for their fans and air conditioners. We determined it's better overall to use some water during the hottest days of the year than to overconsume electricity during the very moments when the grid is most stressed.
Running hotter to use less water
For the past few years, we've been steadily raising the temperature thresholds at which our data centres operate, designing servers to tolerate more heat. If servers can tolerate more heat, they can reduce the number of hours they need water to cool things down. After a few years of iteration, learning, and adjusting, we now use water to cool incoming air only when ambient temperatures exceed roughly 30°C, making the system efficient in most climates.
"This is how we innovate at Amazon," Tinnemeyer says. "We set an ambitious target that benefits our customers, iterate relentlessly, and validate with data — in this case, proving we could cut water use in half without any impact on performance."
To validate the approach, we analysed thousands of hours of data across data centre campuses, checking failure rates at higher temperatures. "The failure rate didn't increase," Schilz says.
The results have been significant: "Our engineers looked at two identical data centres on the same campus and were able to use about 50% less water in one of them that was running with higher temperatures," Schilz says.
For example, in Northern Virginia, our largest region by IT load, we dropped water use by 42% year-over-year, even as demand for computing continued to grow.
75% of the way to water positive
While we're constantly getting more efficient and we're using less water per kWh of server use every year, we want to go well beyond that and actually create more usable water around the world than we consume. So we've committed to being water positive by 2030 and we're already about 75% of the way there.
How do we do that? First, we track how much water we use so we understand how much water we'll need to return to reach our goal. In 2025, we withdrew approximately 9.5 billion litres across our entire global data centre footprint during the whole year. To put that in perspective, the European data centre industry as a whole accounts for less than 0.5% of all industrial water use — and Amazon's European operations use a fraction of even that. And, at the sites we own and operate directly, the total amount of water we withdrew decreased 2% from 2024 to 2025, even as the number of buildings we have around the world continued to grow.
Next, we invest in and invent ways to capture water that would be otherwise wasted and 'return' it to communities that need it.
In Europe, we're investing in water replenishment projects across the continent. In northeastern Spain, we worked with environmental consultancy Mediodes on a pipeline that moves runoff water from upstream fields to a poplar grove in the town of Pina de Ebro, reducing the need to pull irrigation water from the Ebro River. In Germany, we've launched innovative urban leak detection initiatives and wetland restoration projects. In Sweden, we broke ground on a wetland project outside Katrineholm that will reduce flooding risks, improve water quality in nearby lakes, and enhance biodiversity. In the UK, we're working with The Rivers Trust in the Thames River basin, restoring natural flood management and replenishing water resources for local communities. In Italy, we're working with Aganova to reduce water loss using AI-powered acoustic leak detection.
Together, we've announced over 50 water projects expected to return more than 22 billion litres of water annually for use by local communities. That's enough to fill 8,800 Olympic swimming pools.
We're also working to benefit the communities where we operate by using water in our own operations that would otherwise be unusable. We're pioneering the use of this 'reclaimed' water, sourcing from wastewater treatment plants instead of using drinkable water. We already operate 26 facilities using 100% reclaimed water, more than any other cloud provider, with 130 more contracted globally.
"We're not just using reclaimed water," says Usman Khan, a water specialist at Amazon for over seven years. "We're helping communities develop these programmes from the ground up."
For water specialist Beau Schilz, who spent years in water utilities before joining Amazon, it comes back to being a responsible neighbour. "We're particularly focused on areas where there's water scarcity," he says. "Amazon wants to partner with communities to ensure our water stewardship creates local benefits that they want to see."
As demand for cloud computing continues to grow, so does our commitment to doing more with less — and to leave communities better than we found them.
Read more about our water replenishment efforts and see our water withdrawal by region.
