Data centers require massive volumes of water to operate, and the growing use of artificial intelligence means more of these centers are popping up in water-abundant regions such as the Great Lakes. However, despite their access to the vast bodies of water, not all communities in or near the Great Lakes basin have the capacity to sustainably support this industry, experts say.
A recent report warns the region is not prepared for the unprecedented, growing demand from data centers and other water-heavy users — which, if not addressed, could lead to shortages and conflict. The report also points to agriculture as a growing stressor.
Every Great Lakes state has passed tax incentive legislation to encourage data centers to locate there. But these incentives are not “reflective of where water is available — and where it isn’t,” said Helena Volzer, author of the report and senior source water policy manager at the nonprofit Alliance for the Great Lakes.
In addition, data centers are not required to report their water consumption.
The threat reaches far beyond what the eye can see and deep under our feet. The volume of fresh groundwater in the basin is equal to that of Lake Huron, earning it a nickname among scientists: the sixth Great Lake. Alongside precipitation and snowmelt, the inflow from this underground water helps replenish the massive bodies of water. But that still happens very slowly — each year, 1% of the Great Lakes is recharged.
“Those of us who work in this space think of the Great Lakes more as a finite resource,” said Melissa Scanlan, director of the Center for Water Policy at the University of Wisconsin Milwaukee.
And it’s experiencing strain like never before. Last year, the Lawrence Berkeley National Laboratory estimated that in 2023, data centers across the country consumed 17 billion gallons of water for cooling and projected that those figures could double or quadruple by 2028.
Additionally, hotter summers and drought — exacerbated by human-made climate change — are increasing agriculture’s reliance on irrigation.
“There are some gaps that we need to address, to accommodate (the) increase in demand,” Volzer said. State laws and regional planning need to inform economic development decisions that are sustainable.
Illinois is no stranger to some of these emerging threats to its water resources. As of September, it was the fourth state with the most data centers in the country at over 200, behind only Virginia, Texas and California.
These companies are moving into small towns, threatening to deplete municipal water supplies, wells and groundwater. For instance, a data center that could require 3 million gallons of water a day has been proposed in the village of Minooka near Joliet, an area that expects its groundwater supply to dry up in the next five years. Both municipalities and other surrounding communities have entered into a deal with the city of Chicago to purchase water from Lake Michigan.
While Illinois legislation is trying to keep up with the influx of data centers, Volzer said, “it’s not happening fast enough.”
Black box of water use
Phones and laptops overheat during heavy use, such as when several apps or tabs are open simultaneously, or when the devices are being used to play video games or watch movies.
The same happens inside data centers, Scanlan said.
“They have giant servers in these buildings, and they’re generating lots and lots of heat, so they need to be kept cool,” she said. Massive volumes of cold water are circulated through pipes in and around computer equipment, absorbing heat produced by the servers.
The centers also use water in other indirect ways, such as in the production of electricity to power the facility — “in some cases, the equivalent amounts to a small city,” Scanlan said. When that electricity is obtained through fossil fuels, as opposed to solar or wind energy, the production process requires even more water.
“So, part of the water use puzzle is: What kind of technology is being used to cool the centers? And the other part is: How are they getting their electricity?” Scanlan said.
Yet these technology companies rarely reveal how much water they consume. Less than a third of data centers track water use, Volzer said.
“We have a kind of black box around that water usage,” she said. “Then, how can we predict demand?”
About 97% of data center operators obtain water from municipal supplies. This means that, like regular citizens, these companies are considered customers and are not required to publicly disclose their usage or report it to a regulatory body, according to Scanlan.
“So it’s been very difficult to get a handle on how much water is going to this new business,” she said. “That’s part of the difficulty for communities trying to assess: ‘Do we want to host a data center?’ They don’t really have all the information that they need to make a good decision.”
Policy and regulations have yet to catch up.
“And, by design, the information has been obscured,” Scanlan added. “This is an industry that uses nondisclosure agreements and confidentiality agreements when they’re going into communities.”
In Illinois, Democratic state Sen. Steve Stadelman, 34th District, introduced the Illinois Data Center Energy and Water Reporting Act earlier this year to require data centers to report their energy and water consumption every year and to make some of that data available to the public. The bill didn’t advance, but Stadelman expressed hopes that language around reporting requirements will be included in the final omnibus energy legislation the General Assembly could pass this fall or next year.
Stadelman said his concerns emerged in recent years as developers of data centers began moving into the state, resulting in increased energy and water demand. The industry has opposed his bill, the legislator said, by claiming that usage information is proprietary. But some of that information is already shared with utility companies and during the permitting processes at the local level, he added.
“It’s difficult to craft policies to ensure residential ratepayers are not unnecessarily burdened and shouldering the price spikes when we really don’t know exactly how much energy and water data centers use,” Stadelmen said in a written statement to the Tribune.
Incentivizing water use
Most data centers mainly use drinking water for cooling purposes, but this is not necessary. Instead, they could use alternative sources, including reclaimed or treated wastewater to relieve pressure on municipal supplies.
“States need to be exploring … ways to allow for non-potable reuse,” Volzer said. “What is the incentive to use recirculation, to be more efficient? It kind of has to come from the government.”
In Illinois, data centers outside Chicago can hook onto municipal water supplies that often rely on groundwater, which makes up between 20% and 40% of the total water flowing in and out of the Great Lakes system.
“In the Great Lakes region, especially Illinois and the northern part of the state, we’re pretty blessed with the access to quantity and quality of groundwater that we do have,” said Brian Snelten, a former president of the Illinois Association of Groundwater Professionals and the National Ground Water Association. “We forget about it because we can’t see it.”
But as climate change scrambles precipitation patterns, it is putting more pressure on these resources. Even scattered extreme rain events are not enough to replenish aquifers — at least not “in the same way that more subtle, lighter rain events do over time,” Volzer said.
Most of the rainfall runs right off, she said, especially where clay soils with poor drainage, like those predominant in Illinois, don’t easily allow it to seep through.
“You get this conflict between reasonable use for life, and then you have industry that wants to come in,” Snelten said. “The first thing people think about when they hear about the amount of water being used (by data centers) is: ‘Is my well going to go dry?’”
Illinois is also particularly attractive to data centers moving into the region in that it’s the only state that can divert and sell freshwater from a Great Lake.
The Great Lakes Compact — an agreement between the surrounding eight U.S. states and two Canadian provinces — prohibits diversions of water from the basin, but a Supreme Court decree from 1967 allows Illinois to divert over 2 billion gallons of Lake Michigan water via Chicago every day.
It’s how Joliet entered a $1 billion deal with the city of Chicago in 2023, to supply the suburb and five neighboring communities with 105 million gallons of Lake Michigan water a day for at least a century as their groundwater supply depletes. One of those communities is Minooka, where the proposed data center would need millions of gallons of water per day.
While Volzer advocates for scaling back tax incentives or outright eliminating them, she said tax breaks and credits can be coupled with responsible and efficient water use to avoid depleting the resource wherever it may already be scarce.
For instance, Michigan enacted a law last year that authorized tax incentives for new data centers, under the condition that they must connect to a municipal system that has the available capacity to supply water. That legislation is designed, Volzer said, to encourage siting where the resource is available.
“Economic development can happen,” she said. “We’re just saying: Plan for it in a sustainable way.”
Scanlan echoed the need for thoughtful planning around a water supply that is not unlimited.
“So, thinking about how you use your finite resources in a planned way that makes sure you’re maximizing local benefits and local job growth — that’s also, I think, a very smart choice for communities, to enter into that planning,” she said.
Agricultural pressures
Groundwater is the main source of agricultural irrigation in Illinois. And while the region has long relied on agriculture, drought is requiring some states to use more water than before. According to the 2023 Farm and Ranch Irrigation Survey of the U.S. Department of Agriculture, Illinois used 134 billion gallons of water to irrigate almost 680,000 acres of farmland that year, when Illinois had its worst drought in over a decade.
In 2018, the state used 108 billion gallons on almost 565,000 acres; in 2013, which followed a year of particularly bad drought, it used 119 billion gallons on over 540,000 acres.
Additionally, rising average temperatures from climate change are increasing the rates at which the millions of acres of corn crops in Illinois release water vapor into the atmosphere as they mature in the summer. This accelerated process means the crops require more water during their growth stages to avoid stress and yield loss.
Since the Dust Bowl in the 1930s, volunteer-led agencies in Illinois, known as Soil and Water Conservation Districts — 97 across the state’s 102 counties — have helped farmers conserve soil health, control erosion and conserve water resources.
“The soil is very much a living thing, and it has the ability, naturally, to be able to really take in a lot of moisture,” said Eliot Clay, executive director of the Association of Illinois Soil and Water Conservation Districts. Some of that water filters through to recharge aquifers.
While agriculture can contribute to dwindling groundwater resources, Clay said, certain practices can help address the issue.
“It’s not impossible for us to deplete an aquifer,” he said. “What we know for a fact is that, with the adoption of a successful conservation operation on a farm, they are able to decrease the amount of water coming off their landscape and put it back into (groundwater), which essentially is going to be used by people, for either drinking water or industry or what have you.”
Even though agricultural conservation practices — such as cover crops and tillage to improve soil health — can help replenish the resource, Clay called them “largely Band-Aid approaches.”
“Those aquifers took thousands of years to fill,” he said. “And we can do a lot to help make sure that the land is doing the best it can to take up water. … But, is it going to solve the problem? I don’t know.”
The conservation districts act as “the first line of defense” for groundwater, Volzer said, recommending limits to state agencies for high-capacity wells.
Beyond that, however, Illinois has no centralized system for groundwater management, meaning the state can’t proactively address depleting aquifers until after negative effects have occurred. This is because the districts are nonregulatory and can make recommendations for well limits only after receiving a landowner complaint, carrying out an investigation and finding a substantial lowering of groundwater levels.
“I think Illinois is really in need of a more comprehensive groundwater management law,” Volzer said.
The report suggests that Illinois create a centralized, state-level management program for registration, permitting and well siting that limits groundwater use where depletion is likely to occur, rather than where it is already happening. It also recommends that all the Great Lakes states implement energy and water efficiency standards, as well as reporting requirements, for large water users.
Scanlan said a decentralized system might’ve made sense in an earlier time with a smaller population, less water conflict and agriculture that required less irrigation. But not anymore.
“It could be really beneficial for the state to have a bigger picture of what’s going on with (its) groundwater,” she said.
Still, the devil is in the details, Clay said, “in terms of how something like this would develop.”
He believes the benefit of conservation districts is that they provide on-the-ground, personalized technical assistance to farmers and communities to implement resource conservation practices. Centralized groundwater management and monitoring are important, he said, but should be in the hands of a state agency while the districts continue in their nonregulatory role.
“(Conservation districts) are way more important now than they’ve been, because of what’s going on federally,” he said, as the U.S. Department of Agriculture rolls back programs and regulations under the Trump administration. “But, overall, I do think that there’s merit in trying to figure out what the actual usage of groundwater is in Illinois, in a more quantifiable way.”