SPRINGFIELD — Lawmakers emphasized the need for transparency about how much water data centers use to cool their facilities at the final of three data center-focused hearings in the House Executive Committee.

Undisclosed water use is one of the most common complaints about data centers, particularly for the large, hyperscale facilities that support artificial intelligence that are proliferating across Illinois.

“We talk a lot about energy, and people express concerns about, ‘Are we utilizing energy? Are we going to have enough resources there?’ We have a plan,” said Democratic Rep. Ann Williams of Chicago, who chaired the committee on Wednesday. “I think that same process needs to happen with water and how much of it already exists versus what we need to put in place with the influx of users.”

The amount of water a data center uses can vary widely and depends on factors like its size, outside temperatures and how it cools its servers, but one facility can use as much as a small city in a day.

Helena Volzer, senior source water policy manager for the Alliance for the Great Lakes, and Andrew Rehn, the climate policy director of the Prairie Rivers Network touted the POWER Act, a regulation bill currently under consideration in the General Assembly, as the best mechanism to manage water use by data centers.

Volzer said one of the major benefits of the POWER Act is that it begins to address what she described as haphazard water management planning in Illinois.

“There’s really not much in the way of water use reporting or evaluating whether or not the watershed can handle a proposed water use before that water use occurs,” she said of current state regulations.

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Climate change, Volzer added, is threatening water sources with hotter, drier summers and more droughts.

“The connection between groundwater and surface water means that surface water resources can become stressed if groundwater becomes depleted,” she said. “With simultaneously competing demand for water from agriculture, industry, data centers and residential use, communities in Illinois are facing complex tradeoffs in managing primary water supplies.”

The POWER Act requires data centers to produce plans for water use, scarcity and sustainability. It also requires data centers to use the most water efficient cooling method — using closed loop cooling as a baseline for efficiency — and to report that usage four times a year to the Illinois Power Agency and to a publicly accessible website.

The POWER Act also requires data centers to submit their plans for review from the Illinois Water Survey, a nongovernment group that monitors water supplies across the state.

Rehn said the frameworks in the POWER Act will give residents more clarity on how much water data centers use and assuage fears if that amount is lower than they expected.

“We are asking for a plan that’s just a document that says, ‘here’s what we’re going to do,’” he said. “I personally think transparency will shed daylight and let folks be more comfortable if the water usage is indeed that low. That seems like an easy thing to do.”

Pushback

Brad Tietz, the Midwest policy director for the Data Center Coalition, pushed back on the planning requirements, arguing that data center developers already work closely with utilities and municipalities to make plans and ensure the facilities will have the cooling resources they need.

The data center industry opposes the POWER Act on the grounds that it singles out one industry when there are others that use a lot of water and aren’t under the same scrutiny.

Compared to agriculture, some manufacturing and golf courses, he said, data centers are much more water efficient.

Tietz also said data center cooling methods are constantly evolving, and innovations include building near water treatment plants or using cooling methods that involve non-potable water, recycled water or air.

He said those methods are possible in Illinois, especially given its cooler temperatures, which could allow data centers to use air cooling outside of summer months. He acknowledged that some of those methods require more energy, and the choice depends on the hardware in the facility.

“Cooling data centers involves inherent tradeoffs,” Tietz said. “Air cooling tends towards higher energy use, while liquid and evaporative methods typically require more water. Selecting a cooling technology therefore becomes a matter of balancing energy consumption and water usage.”

Lawmakers said those developments don’t change the need for transparency about how data centers operate in communities.

Rep. Theresa Mah, D- Chicago, said she didn’t understand why the industry objected to making project plans public.

“I live in a community where there’s a data center nearby and it’s been important for my constituents and myself to know what’s happening there and to have that transparency,” she said. “It seems like it just makes sense for everywhere else in the state as well.”

Williams said managing water needs in Illinois requires information about large water users to be available for everyone and data centers are a good place to start.

“I know every data center company is different, but what’s the objection to providing that upfront transparency?” Williams asked. “This is a new large user. I get what you’re saying. There are other users out there, certainly that there have been for some time, but with this influx of new users, it seems like planning would be helpful.”

Democrats in the Senate have held hearings about statewide groundwater management and are considering how to approach the issue.

Capitol News Illinois is a nonprofit, nonpartisan news service that distributes state government coverage to hundreds of news outlets statewide. It is funded primarily by the Illinois Press Foundation and the Robert R. McCormick Foundation.