Article summary
- Months of drought and high temperatures have affected water levels in Illinois, raising concerns about water supply.
- These concerns are exacerbated by the development of data centers, especially in areas where aquifers have been depleted.
- Water availability varies across the state because different regions rely on different water sources, and some water is more readily available than others.
- Advocates say Illinois needs a clear picture of who is responsible for overseeing water use and a focused plan for how water use will be managed.
This summary was written by the reporter and editor who worked on this article.
Drought and high temperatures have plagued Illinois since last summer, and although rain this spring improved conditions, the prolonged lack of precipitation and high temperatures are impacting water supplies across the state.
For example, Sullivan, a small city southwest of Decatur, declared a water emergency in February that is expected to last through June. The City of Bloomington recently lifted its severe drought declaration and eased water usage restrictions, but residents are encouraged to continue to be prudent. The Illinois Department of Natural Resources has postponed the opening of Heidecke Lake near Morris to boating due to low water levels.
As local governments face water challenges, regional droughts have focused attention on lax or non-existent water management policies in Illinois. State lawmakers are also paying close attention to the issue, especially as they consider how to regulate a new type of high-end water user that is expanding in the state: data centers.
Illinois State Climatologist Trent Ford said monitoring and managing water can be difficult.
“There’s no question that Illinois’ water system is a really, really complex problem,” Ford said. “You know, there’s always this overarching perception of water abundance, sometimes too much. But it’s never like that. It’s just a perception. It’s a mirage of abundance.”
He said rainfall in 2026 had improved topsoil moisture, but months of drought meant the dryness was affecting deeper layers of soil and water. He said important rivers such as the Sangamon, Mackinaw, Kankakee, Iroquois and Mason rivers are “still well below normal levels for this time of year,” but he expects water levels in those rivers to improve.
Meanwhile, state lawmakers in Springfield are still in the early stages of considering a statewide water use plan, debating the issue primarily in open-topic public hearings. But the onset of data center development has at least brought this discussion to the forefront.
“There are some agencies that touch on this issue, but then it’s under local control,” said Sen. Rachel Ventura, D-Joliet. “There are multi-state and multi-country water compacts in the Great Lakes, which means this is not something that can be easily implemented and completed.
“The goal, of course, is to make sure the state protects its water so people can have a high quality of life.”
water monitoring
People in Illinois rely on lakes, rivers, shallow groundwater, and deep groundwater, but water supplies can be difficult to measure because they depend on the region of the state and the structure of the ground below the surface.
“It’s rapidly becoming more complex under our feet,” said Daniel Abrams, principal investigator at the Illinois Water Survey. “It’s important to be able to understand that. And we’re looking at all kinds of ways to visualize that and improve it.”
Although Water Survey is not a government agency, it works with the Illinois Department of Natural Resources to survey and monitor water supplies using wells that measure groundwater levels and data mapping tools that visualize Illinois’ hydrology. Water studies also advise municipalities and counties on water management.
The Water Survey conducts important research, but its mission is made difficult by the lack of state regulatory authority over water.
Abrams said water supply modeling is an important tool for water management, but it’s not perfect, and he and his team are always looking for more data, especially on water use.
“One of the data sources that we have available at the moment is annual demand,” he said. “But the more you start thinking about drought, the more you start thinking about peak demand situations.”
Shallow aquifers and surface water sources are susceptible to drought in the short term, Abrams explained, but quickly recover when the rains arrive. The opposite is true for deep aquifers, such as the Mahomet Aquifer in central Illinois and the deep sandstone aquifer systems in northern Illinois. This means that drought and overuse have different impacts depending on location.
With more frequent reporting from local governments, irrigators and industry, water quality surveys would provide more accurate information about how seasonal demand works and the status of aquifer levels, he said.
“Having information on a quarterly or monthly basis could improve the accuracy of our models and help us better understand things like the impact of drought on water supplies,” said Jenna Shelton, director of the Illinois Water Survey.
The Illinois Water Inventory Program collects reports on water withdrawals, but lacks data and does not provide a complete picture of that demand.
Since 2010, the Water Use Act of 1983 requires annual water usage reports for “all large-capacity wells or water intakes that pump 70 gallons per minute (100,000 gallons per day) or more.” Well and intake systems with a combined pumping rate of 70 gallons per minute or more also qualify.
These capable organizations include public water providers such as municipalities, industrial and commercial facilities, wildlife and recreation operations, and agricultural irrigation facilities.
Sources told Illinois Capitol News that enforcement of reporting requirements across the state is lax.
“We are not a government agency. We cannot force industry or farmers to report their water use to us every year,” said Jenxin “Jason” Chan, principal investigator at the Water Quality Institute, which leads state and local water supply plans. “You can’t achieve 100% compliance.”
Water use reporting is key to understanding what the state needs in the future and how to plan for it, he said. Without that information, resource planning becomes much more difficult.
management and planning
Nora Beck, an official with the Chicago Metropolitan Planning Agency (CMAP), said the state needs to update its rules regarding who is responsible for water resources so it can better manage its water resources.
“All legislation has been piecemeal over time,” she said.
CMAP provides water supply planning in northeastern Illinois. For people outside of Chicago and its surrounding areas, there are many water supply issues as water levels have declined dramatically and depend on aquifers that are difficult to replenish.
For example, a 2018 report from the Bureau of Water Research predicted that if Joliet continues to use the aquifer, it will not be able to meet its water needs by 2030, so the city is transitioning to Lake Michigan as its water source.
In Illinois, the relationship between the Great Lakes and St. Paul’s Great Lakes limits the amount of water that can be taken from the lakes. Lawrence River Basin Water Resources Agreement — An agreement between eight Canadian provinces and two provinces regarding Great Lakes water quality and water withdrawals. That limit doesn’t exist for groundwater, Beck said.
Beck said about 80 percent of the residents CMAP serves rely on Lake Michigan for their water, while the rest rely on groundwater sources.
“Basically, we have a water budget for the Lake Michigan property,” she said. “The remaining 20% is mainly used for groundwater sources with no clear budget. Users can pump as much as they want.”
Sen. Ventura, a Joliet native, has been involved in water policy since working as a naturalist for Georgia State Parks and Historic Sites.
She said a wise approach to management would be to consider each water body in Illinois individually and streamline oversight authority. Ventura also suggested that the state emulate the Great Lakes Water Compact and create water use agreements across Illinois.
“Doing regional studies is still very important,” Ventura said. “And I think it’s important for everyone in our state to look at things like backfilling aquifers and having long-term plans for access to water.”
There’s also no single agency governing water use in Illinois, she said. IDNR, IEPA, and the Illinois Department of Agriculture all manage water at different levels and with different focuses.
Of the three agencies, IDNR has the greatest responsibility for water supply, working with groups such as CMAP, the State Water Planning Task Force, and the Water Survey for regional planning and monitoring. However, at a February public hearing on groundwater, an IDNR representative said the agency faces severe staffing shortages, which limits its ability to monitor usage and enforce reports.
Since 2024, CMAP has worked with IDNR, Illinois-Indiana Sea Grant, and the Northwest Water Planning Alliance to develop water sustainability plans for five counties in northeastern Illinois. Beck said a statewide version of that could be helpful.
Beck also discussed governance strategies with the Freshwater Association, Minnesota’s effort to better manage drinking water. Minnesota is currently developing updated rules for groundwater governance.
“I don’t think we need to copy directly from other states,” Beck said. “But I think it’s important to note that these other states recognize that they need to improve their groundwater governance and are doing so in some way.”
Other solutions
Mr. Ventura has introduced or co-sponsored bills that would give the Illinois Department of Agriculture more authority over some water withdrawals and impose more restrictions on private companies that buy water from municipalities. However, these measures have stalled.
He has also proposed a data center regulation bill that would require facilities to submit water usage reports and monitor wastewater for pollutants, a provision that could become part of a broader data center regulation bill.
The POWER Act, a widely discussed data center regulation bill, has several water-related provisions, including requirements for usage, efficiency, and water quality monitoring.
“We’re looking at the hundreds, thousands, millions of people who need access to water, and we’re thinking about what that will look like in the future as we address data centers and other climate change concerns,” Ventura said.
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