Data centers drain California’s water with little public oversight

from Rachel BeckerCalMatters

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Data center builders don’t tell the public how much water they use, according to a new report — and the industry is moving into water-poor and vulnerable communities.

The report by think tank Next10 and researchers at Santa Clara University found that planned data centers – the ganglia of artificial intelligence – are distribution to regions relying on excessive groundwater and stressed surface water, with potentially large effects in the Central and Imperial Valleys.

But, strengthening previous studies, researchers found that a combination of state, federal, and local policies allowed data center operators to avoid publicly disclosing their actual water usage.

California lawmakers tried address last year, but California Gov. Gavin Newsom vetoed the measure. Now the Legislature is trying again, with accounts mandated disclosures on water use and planning.

“We have this huge construction and we have very little data,” said Irina Raikuwho directs the Internet Ethics Program at Santa Clara University’s Markkula Center for Applied Ethics.

Coupled with California’s uncertain water supplies, Raiku said, “it’s just not a good combination.”

Shaolei Renan expert on the environmental impact of artificial intelligence at UC Riverside, who was not involved in the study, said the findings point to a much broader problem.

“Limited publicly available information about data center water use makes it difficult for communities, water providers and researchers to have meaningful public discussions and responsibly evaluate electricity-water trade-offs,” Wren said in an email.

Using cloudy water

Few environmental impact reports for California data centers are publicly available online, the researchers found.

Raiku et al Iris Stewart-Freyprofessor of ecology, went to look for the reports, aims to evaluate and reveal a project’s impact on both nature and people under California’s landmark Environmental Quality Act.

They almost didn’t find it. The ones they found were mostly for facilities in the city of Santa Clara.

Through interviews with planning officials, they found that projects can slip by with few environmental reviews if they fall below certain thresholds for size or water use, or if they meet city or county criteria for other approval paths. They include something called ministerial approvalwhich requires planning agencies to approve a project that meets local zoning and other standards.

Even for data centers that are subject to stricter environmental controls, the researchers found that documentation is rarely available to the public.

In the few cases where planning documents were made public, information – about the owner or operator of the data center, the size, type of cooling system, the amount of water used, whether recycled or potable – was often “missing, conflicting or unclear”, the report said.

The researchers said they contacted water suppliers in areas where the data centers are clustered, seeking usage data. No one answered.

Moving to vulnerable regions

California data centers are clustered primarily in the southern San Francisco Bay Area and the city of Los Angeles, with smaller concentrations in Sacramento and San Diego.

But the report noted large, planned projects in rural and less affluent regions — such as Gilroy in Santa Clara County, as well as the heavily agricultural Imperial Valley.

“They need a bunch of cheap land,” Raiku. “If we’re not careful, they’ll end up being targeted, very convincingly, at communities that have real needs — without paying enough attention to the water part.”

Khara Boender, director of state policy for the Data Center Coalition, which has opposed bills requiring more detailed reporting of water use, said in an email that the industry is “committed to being a good neighbor.”

Boender claims that data centers collectively “use significantly less water than other major industries in 2025, including the agriculture, power, food and beverage, and semiconductor sectors,” but the coalition offers no data to back that up.

Collective use matters less than local impacts in a state where each community has its own mix of water supplies and strains, according to a previous study published by a team at UC Berkeley.

Whether data centers use a lot or little water compared to agriculture or other industries, “what matters most is the scale of new local use compared to available local supplies,” the Berkeley team concluded earlier this year. “Unfortunately, this picture is clouded by flaws in the data.”

In this week’s report, the Santa Clara University team sampled those local supplies and community vulnerabilities to the expected expansion.

“We’re on the verge of that happening in California,” said Stewart-Frey, an environmental scientist. Her report, she added, does not advocate against data centers. But “communities need to know what they’re getting into.”

Debate over proposed data centers erupts in Kern County desert community with declining groundwater and in the hot Imperial Valley, drawing on the stressed Colorado River.

Residents of Monterey Park in the San Gabriel Valley successfully opposed one data center project because of environmental concerns and inadequate information and provided an upcoming vote on a citywide ban.

c letter to city authoritiesa representative for the developer dismissed the naysayers as “pissing off an uninformed mob to pressure decision-making.”

Raiku pushed back. “If these communities aren’t informed about the problem — whose fault is it? Who’s supposed to inform people so you don’t have this kind of pushback if there’s no need for it?”

New Laws Against Big Tech

last year, Diane Papan MPSan Mateo Democrat, author of a bill requiring data center operators to report estimated or actual water consumption to their water supplier when seeking or renewing a business license or permit.

Gov. Gavin Newsom vetoed the measure amid industry pressuresaying it was “reluctant to impose strict reporting requirements on the operational details of this sector without understanding the full impact on businesses and users of their technology”.

Now Papan tries again with two bills. one largely repeats last year’s measure, requiring additional reporting to the city and county. The other would prohibit local authorities from approving new or expanded data centers unless the developer discloses information about their water use and plans.

It will also set other requirements – such as banning development in exceeded groundwater basins, such as in the San Joaquin Valley, unless state water managers approve it.

“You can’t manage what you don’t have and you can’t measure,” Pappan said. “The public likes transparency, and they should.”

Both bills cleared a key legislative hurdle this week but faced stiff opposition from the tech industry and business groups.

“If they run out of water, guess what happens? And they can’t cool their systems – will they be able to?” Pappan said. “To which I say, help us help you.”

This article was originally published on CalMatters and is republished under Creative Commons Attribution-NonCommercial-No Derivatives license.