Companies that run data centers are facing increasing scrutiny for guzzling water in the dry western U.S. as artificial intelligence fuels a boom in the industry.
California legislators passed a bill this month that would require the facilities to report their projected water use before they begin operating and thereafter certify how much they use annually. The bill is now awaiting Gov. Gavin Newsom’s signature.
“Data centers are popping up all over the place,” said Assemblymember Diane Papan (D-San Mateo), the bill’s author. “And they demand so much water.”
The large buildings packed with equipment typically use water to cool their servers and interiors.
The International Energy Agency said in a recent report that a 100-megawatt data center in the U.S. can consume approximately 500,000 gallons of water per day. But it said innovations in cooling systems can significantly reduce that.
The California legislation requires companies to submit water information for both new and existing facilities.
“It’s very important that localities be able to plan for what’s next, whether that’s building more housing or building data centers, and data centers happen to be incredibly thirsty,” said Papan, who chairs the Assembly Water, Parks and Wildlife Committee.
Much of the nation’s data center construction boom is taking place in arid states, including California, Arizona and Texas, where strains on water have been mounting amid dry conditions and rising temperatures.
The ongoing water shortage on the Colorado River, where reservoirs are approaching critically low levels, is expected to force additional reductions in water use in the Southwest in the coming years.
A key goal is to prevent problems, Papan said, “so that we don’t end up with a data center without sufficient water, and we don’t end up with a community that has a data center that takes too much water away from the community.”
Assembly Bill 93 was opposed by business groups including the Data Center Coalition. Newsom has until Oct. 12 to sign or veto it.
In a report released this week, researchers with the nonprofit group Ceres analyzed current and projected water use for data centers in the Phoenix area, where, as of May, there were 75 of the facilities and 49 more planned. It found that water for cooling, as well as water consumption linked to electricity generation, is expected to dramatically increase in the coming years as more facilities come online.
The group projected that cooling water alone in the area could increase to more than 3.7 billion gallons per year, enough to supply a city of about 80,000 people for nearly two years — a change they said could increase water stress in a region that is already grappling with scarcity.
“This needs to become a consideration in those areas,” said Kirsten James, senior director of Ceres’ water program. “If companies and their shareholders do not address these sustainability risks, then that could leave them open for financial loss, and so they really need to be proactive.”
Experts say California has more than 300 data centers, with many more planned.
Some major tech companies already disclose their data centers’ water use in other parts of the country, so it makes sense for the state to collect this information, especially since California is known for both leading on innovation and for having long droughts, said Shaolei Ren, an associate professor at UC Riverside who studies data centers’ use of resources.
“We ask California residents to switch to artificial turf and display ‘water conservation’ stickers in public places, yet data center water use remains hidden,” Ren said. “Disclosure doesn’t hurt the industry or add costs; it simply helps us track and manage a vital resource more responsibly as we build the next generation of data centers.”
Inside data centers, servers generate heat as they run, and are typically cooled by systems that circulate either liquid or air through them. Many data center buildings have industrial-scale cooling towers where water evaporates and helps cool the interior environment.
Some use much less water than others. Facilities with closed-loop dry coolers may use virtually no water on-site, while those that rely on evaporative cooling are more water-intensive, Ren said.
Notably, the types of systems that require little water are generally more energy-intensive and costlier, Ren said.
The rise of artificial intelligence as well as growing investments in cloud computing are driving the data center construction boom. While some companies don’t report their water use, others do.
Google, for example, listed water data for three dozen data centers around the world in its latest annual environmental report, saying a single site can use anywhere from nearly zero water to more than 3 million gallons per day, depending on its cooling design and size.
It said some of its more water-intensive centers, including two in Iowa and Oklahoma, require five to six times as much water as an average golf course, while various other facilities use less than a typical golf course. None of the data centers the company listed are in California.
Google said it is focused on “advancing responsible water use,” and that last year, 72% of its water “came from sources at low risk of water depletion or scarcity.”
Michael Kiparsky, director of the Wheeler Water Institute at the UC Berkeley School of Law, said requiring data on water use is a good first step, but local officials may not know what to do with that number alone.
For example, he said, it won’t let them know if there is a more conserving option, or another location with more water available.