Water-guzzling data centers spark worries for Minnesota’s groundwater

Minnesota is one of several U.S. states where companies are building mega-scale data centers to keep up with the explosion of artificial intelligence and cloud computing.

Many data centers use water — sometimes in large amounts — to cool their equipment. That’s raising some concerns about their impacts on the state’s groundwater supplies. 

A single large data center can use as much water as thousands of homes, or “equivalent to a city,” said Carrie Jennings, research and policy director at the nonprofit Freshwater. 

“If you think about where we’re already seeing depletions of groundwater or cones of depression, it’s in those outer-ring suburbs that are getting away from the surface water source of the Mississippi or the Minnesota River,” she said. “They’re exclusively using groundwater.”

Those are the same places where several large data centers are planned or under construction. But pinpointing the exact number of centers or how much water they’ll use can be a challenge, even for state regulators.

“We hear about them in different ways, and that’s part of the challenge,” said Jason Moeckel, assistant director of the Minnesota Department of Natural Resources’ ecological and water resources division.

While reviewing a project, local officials sometimes ask the DNR about any issues with a large water user coming to their city or county. But the details are often vague, Moeckel said.

“Oftentimes what we’ll hear is ‘an industrial water user.’ They won’t even say if it’s a data center,” he said.

Minnesota law requires a water-use permit for industries, farmers or anyone else who draws more than 1 million gallons a year. But some data centers get their water directly from a city system, bypassing the need for a state permit.

A mid-sized data center consumes about 300,000 gallons of water a day, but that number can be much higher for hyperscale data centers.

Cities have water plans ensuring they have adequate water for future growth. Communities in the seven-county metro area also have comprehensive plans through the Metropolitan Council. But most were written before the recent explosion of large data centers.

Moeckel said when it’s consulted about a project, the DNR can help cities identify potential red flags with a high-volume water user.

“There are pockets of places where we know there are some real challenges,” he said. “There are other places where we’re beginning to get a picture of some of the challenges or the constraints.”

Some residents who live near proposed data centers also worry about their water use. Cathy Johnson lives near a large data center campus planned for Farmington and helped start the Coalition for Responsible Data Center Development.

“When water is taken out of one source at that rate, it will have an impact on the surrounding private wells,” Johnson said.

Whether Minnesota has enough water to support data centers may depend on their design and how they’re cooled. Industry representatives say they’ve gotten much more efficient and innovative in their design.

Some tech companies have sustainability goals to save water and energy. They’re building data centers with closed-loop systems that recirculate water to cool equipment. Others use air, wastewater or other fluids for cooling, saving high-quality groundwater for drinking. But those can add time and up-front expense to a project.

There are lots of opportunities for data centers to reduce water use, said Michelle Stockness, Freshwater’s executive director. But she said there needs to be more transparency when cities are approving big water users.

Stockness said some companies are eager to get their projects approved quickly. And they sometimes require local officials to sign non-disclosure agreements, limiting the information that’s available, she said.

“I wish we could help corporations lean into those goals more, with more options in the speed of which they need the decisions to be made,” Stockness said. “That’s the tricky part.”

Some Minnesota lawmakers are calling for more regulations on data centers, although it’s unclear whether they will pass this year.

State Sen. Bill Lieske, R-Lonsdale, represents a district that includes southern Dakota County, which is experiencing a data center boom. He authored a bill that restricts data centers larger than 800,000 square feet to industrial districts.

As a Republican, Lieske says he believes in local decision-making. But he's concerned local officials are sometimes wowed by the economic benefits of data centers, and don’t consider the wider impacts.

“All these towns, they think, ‘Oh, hey, it’s not a big deal for my small town,’” Lieske said. “Yes. But if you draw that much water and electricity, it’ll affect the next small town over.”

Lieske’s bill has bipartisan support. Sen. Erin Maye Quade, DFL-Apple Valley, is a co-author.

Maye Quade also introduced her own bill to fund a study of the environmental impacts of artificial intelligence, including data centers, which she calls a “downstream problem.”

“I think the real problem is upstream, with this rapid expansion of generative AI into our lives in some really insidious ways,” Maye Quade said.

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