Artificial intelligence has a real heat problem.
Cooling next-generation computer chips for AI requires either millions of gallons of water or huge amounts of electricity. Both have ignited sharp opposition from the public.
The industry’s heat trade-off threatens to deepen its unpopularity in communities where concern is growing about the financial and environmental toll of data centers. If a company chooses to save water when cooling a facility, its power needs surge. If it reduces electricity, its water use climbs. One option increases carbon emissions and strains the electric grid; the other depletes a natural resource.
“There’s no easy answer — it’s a lot of trade-offs,” said John Ikeda, chief mission officer at the Water Environment Federation, a technical and educational nonprofit for water professionals that has worked with Amazon on data center issues.
POLITICO spoke with four of the biggest technology companies about how they choose to use either water or energy to cool their facilities — knowing that either one will tax resources and drive public backlash.
Microsoft and Quality Technology Services have pledged to use zero water, in return for higher power usage and potential carbon emissions. Google and Amazon say they use water to reduce pressure on the electric grid in wetter climates, but not in drought-prone areas.
While companies are prioritizing different risks, most are trying to find innovative solutions to their heat problems. Amazon has developed a system that lowered the company’s North American water use by 946 million liters in 2024 — enough drinking water for 1.3 million people a year. And the company improved its water efficiency by 17 percent that year. Microsoft is experimenting with new technologies that allow AI computer chips to function at higher temperatures, potentially reducing power demand for cooling.
“The warmer the temperature, the more efficient the energy use,” said Steve Solomon, Microsoft’s vice president for data center infrastructure engineering
Even so, the sheer volume of water or power needed for the facilities has led to public backlash. Seven out of 10 Americans are opposed to data centers, according to a recent Gallup poll, citing water use as a top concern.
In the first quarter of 2026, at least 75 projects valued at $130 billion were disrupted by local opposition, according to the tracking company Data Center Watch. And county-level moratoriums are becoming increasingly common.
“You can cool a data center without a single drop of water, but it’s very energy-intensive,” said Ikeda, who has worked with technology companies to help utilities understand the water needs of data centers.
“Or you could go 100 percent water for cooling and drop your energy usage, but depending on the time of year or temperature, you’re going to be competing with the community water needs.”
In other words, water use, electricity demand and carbon emissions are tightly linked. Optimizing one often means worsening the other. And almost no one outside of the companies has enough information to assess the impacts — because the industry rarely shares details about its processes.
One problem for local governments that are wrestling with whether to green-light data centers is the lack of transparency. Most tech companies don’t fully explain the details behind their water power trade-off. There is no federal disclosure requirement, and the operators that do share information through sustainability reports use mismatched metrics and varying levels of granularity.
“No other major U.S. energy-consuming sector, nor one which is growing so quickly from economic and infrastructure perspectives, suffers from as many public data blind spots as U.S. data centers,” Eric Masanet, a data center expert at the University of California, Santa Barbara, testified before Congress in February.
Water can shave peak load
Cooling data centers is a matter of basic physics. The computer chips powering the digital economy can easily overheat and shut down, like any laptop.
An unprecedented heat wave in the United Kingdom in 2022 forced Google and Oracle to shut down cloud-computing facilities as temperatures climbed past 100 degrees Fahrenheit.
“Back in the day, you just open the windows and, just like your house, you bring in cold air,” Ben Townsend, Google’s head of infrastructure and sustainability, told POLITICO.
“And then in the summer, when opening the windows isn’t enough, you close the windows and you turn on the air conditioning.”
But as computer chips began working harder, and summer days got hotter, air conditioning large buildings became increasingly inefficient, requiring hundreds of megawatts of electricity — as much as a small power plant. To save energy, most data centers began cooling their systems with water. It can absorb and transport heat more efficiently than cooling the air in a building. Imagine plunging into a cold ocean compared to cranking the AC.
“Water just has this uniquely impressive power of reducing energy consumption, and then all the grid constraints and emissions that come with it,” Townsend said.
Google’s own calculations show that using 264 million gallons of water for cooling in central Europe can reduce a data center’s power demands by 41,000 megawatt-hours — enough to power 10,000 homes.
Most hyperscale data centers now use a water-intensive process called “evaporative cooling” during at least part of the year to reduce energy demand. There are several ways to evaporate water for cooling, but the strategy generally uses water to absorb heat from the data center and then releases vapor into the atmosphere — similar to cooling towers used by power plants.
The technology is sometimes deployed in water-deprived areas, potentially taxing natural resources. One recent report found that two-thirds of U.S. data centers built since 2022 are in areas experiencing high levels of water stress.
So newer facilities have begun using more advanced methods, such as adiabatic cooling — when outside air that’s sent through a data center is first sprayed with water to cool it down. Hybrid systems evaporate water during the hottest times of the year, but use outside air for the majority of days.
Amazon Web Services is planning a facility in Louisiana that the company says will use outside air for cooling during “87 percent of the year.” By using evaporative cooling the rest of the year, Amazon will reduce the facility’s electricity demand by 25 to 35 percent “at the same time when the grid experiences peak summer loads,” said Beau Schlitz, who leads the company’s water infrastructure strategic initiatives.
AWS said facilities in more temperate climates, such as in Ohio, may only require water-based cooling for 3 percent of the year.
In any climate, the reasons for using water go back to saving electricity.
“We are trying not to constrain the grid when the grid is the most constrained already with everyone running their ACs,” Schlitz said. “On hot days when everybody wants to cool their homes, we are using water to shave our peak power use down.”
Google and Amazon say such advancements have dramatically reduced their water use. Google’s global fleet of data centers consumed 8.1 billion gallons of water in 2024, according to sustainability documents. The company said that amount is equivalent to the irrigation needs of a mere 54 golf courses.
Amazon data centers used even less water in 2025 — 2.5 billion gallons, or roughly 5 percent of Seattle’s annual water usage. That corresponds roughly to a 2 percent reduction in water use.
Google and Amazon prioritize water saving techniques in specific drought-prone areas, such as Phoenix, and Cape Town, South Africa.
“In areas of high stress or scarcity, no evaporative cooling towers, it’s a hard no,” said Google’s Townsend.
That helps ensure data centers don’t run out of the resources they need to operate.
“Using recycled water also limits risk for our business as well — we don’t want to use potable water for cooling where there may not be enough water supply in the future,” Schlitz said, noting that Amazon has helped build water recycling plants in Loudoun County, Virginia.
Even as data centers try to use less water, the sprawling facilities often find opposition based on the sheer amount of resources they consume. When one arrives in a new location, it inevitably ramps up water use and competes with other large consumers.
“You’ve got property development, cities, dairies, agriculture, ranches already competing for water resources, and now throw on top of that data centers,” said Andrew Coppin, who helps ranchers and farmers track water use through his business called Ranchbot.
“I don’t know about you, but I’d prefer to be able to still have a steak and some salad than ChatGPT.”
And when data centers use less water, they need more power.
Take two Google facilities in Nevada. One in Las Vegas used 359.9 million gallons of water for cooling in 2024, according to sustainability documents, lowering its power use. Another, in Reno, required more power because it was not equipped with evaporative cooling.
“As you move away from evaporative cooling towards air-based cooling, energy consumption goes up dramatically, as do the emissions,” Google’s Townsend said. “And so when we first got started, we evaluated: What would a zero water use target look like, and the forecasted emissions was something we had to take seriously.”
Zero-water promises
The basic choice of water or power remains in play even as technology companies unveil newer, faster computer chips to power AI. Those chips can process so much more information in a given time period that they overheat even faster, leading companies such as Microsoft and Amazon to develop an additional layer to cool them.
It’s known as closed-loop cooling.
It involves running liquid through a cold plate that touches the computer chips. The systems have no outlet for the liquid, and don’t increase a data center’s water usage once they are filled.
Closed-loop cooling has become a buzzword for developers who are attempting to assuage local concerns about a facility’s water use. Communities sometimes request that the method be used. A spokesperson for Quality Technology Services, a major data center developer, said every facility QTS has built since 2019 uses a closed-loop cooling system. The company anticipates the number of new data centers with “water-free cooling systems” will more than double over the next three years.
“We expect our [water reduction metrics] to continue to rapidly improve as these buildings become operational,” the spokesperson, Stephanie Blakely, said in an email.
But even data centers that are equipped with these systems need to remove heat from the liquid loop — and the data center building itself. At Amazon and Google, that means using some form of evaporative cooling.
Microsoft has taken a different approach.
It sheds heat from the closed-loop system by using air to dissipate heat, increasing its energy use.
“But the trade-off is zero water,” said Microsoft’s Solomon.
Amazon’s Schlitz said the promise of zero water can be misleading. “There’s a lot of confusion out there” about closed-loop systems, he said.
While closed loops reduce water, operators still need to reject heat from the loops and from the buildings. And water is often the most effective method, especially when it’s above 85 degrees, he said.
Townsend said that the companies’ different approaches to closed-loop systems can be confusing, or even intentionally misleading, for communities that might associate them with zero water use.
“You really don’t know how they’re cooling their data center unless you ask the specific question, ‘How is your cooling plant rejecting heat? Is it air cooled chillers, dry coolers or evaporative cooling towers?’” he said. “And then you can really understand if there’s consumptive water use or not.”
Companies’ reluctance to share detailed information has created a “PR nightmare,” said Masanet of UC Santa Barbara, adding that it stokes public mistrust.
“A big challenge in this space right now is that there is a lack of transparent and consistent information that’s reported,” said Lindsay Rogers, a policy manager for municipal conservation at Western Resource Advocates, a climate advocacy group.
“I think that secrecy has led to a lot of the public backlash we’ve seen on these projects,” she said.
