Drought and hot temperatures have burdened Illinois since last summer, and despite rain improving conditions this spring, the long-term lack of precipitation and high temperatures have impacted water supplies across the state.

Sullivan, a small city southwest of Decatur, declared a water emergency in February that’s expected to last until June. Bloomington recently ended its severe drought proclamation and eased restrictions on water use, but residents are encouraged to continue being judicious. The Illinois Department of Natural Resources has delayed opening Heidecke Lake near Morris to boating because of low water levels.

As local governments confront water challenges, regional droughts have called attention to lax or nonexistent water management policies in Illinois. State lawmakers have caught on, too, especially as they consider how to regulate data centers, a new type of high-end water user that’s been spreading across the state.

Trent Ford, the Illinois state climatologist, said water monitoring and management can be tricky.

“It is definitely a really, really complex thing with water systems in Illinois,” Ford said. “You know, there’s always this overarching kind of perception of water abundance, in some cases overabundance. But that’s definitely not the case. That’s only a perception. It’s a mirage of abundance.”

He said rain in 2026 has improved topsoil moisture, but months of drought mean the dryness has impacted deeper layers of soil and water. Critical rivers like the Sangamon, the Mackinaw, the Kankakee, the Iroquois and the Mason, “are still way below where they normally are this time of the year,” he said, though he expects those levels to improve.

Lawmakers in Springfield, meanwhile, are only in the early phases of considering statewide water use plans, mostly discussing the problem in nonvoting subject matter hearings. The onset of data center development, however, has at least brought the conversations to the forefront.

“There’s several agencies that touch on this, and then you’ve got local control that does things,” Sen. Rachel Ventura, D-Joliet, said. “You’ve got the multi-state and multi-country water compact of the Great Lakes. So this is not just something that you can easily introduce and then be done.

“The goal of course is to make sure that our state is safeguarding water so people can have quality of life.”

Water monitoring

Illinoisans rely on lakes, rivers, shallow groundwater and deep groundwater, but measuring water supply can be difficult because it depends on the region of the state and the structure of the ground beneath the surface.

“Underneath our feet gets really complicated really fast,” said Daniel Abrams, a principal research scientist at the Illinois Water Survey. “Being able to understand that is critical. And we’re looking at all kinds of ways to image and improve that.”

The Water Survey is not a government agency, but it works with the Illinois Department of Natural Resources to conduct research and monitor water supply by using wells that measure groundwater levels and data mapping tools that visualize Illinois’ hydrology. The Water Survey also advises municipalities and counties about managing water.

The Water Survey does important research, but the lack of state regulatory authority over water makes its task difficult.

Abrams said water supply modeling is a crucial tool for water management, but it’s not perfect, and he and his team are always looking for more data — particularly about water use.

“One of the data sources that right now we have is annual demand,” he said. “But the more we start thinking about drought, the more we start thinking about those peak demand conditions.”

Shallow aquifers and surface water sources are more susceptible to drought in the short term, but they rebound quickly after rain, Abrams explained. The opposite is true of deep aquifers like the Mahomet Aquifer in central Illinois or the deep sandstone aquifer system in northern Illinois. That means drought and overuse have different effects depending on the location.

More frequent reporting from municipalities, irrigators and industries would give the Water Survey a better idea of how seasonal demand works and the condition of aquifer levels, he said.

“Getting information on a quarterly basis or a monthly basis would make our models more accurate and could help us better understand things like impacts of drought to our water supply,” said Jenna Shelton, director of the Illinois Water Survey.

The Illinois Water Inventory Program collects reports about withdrawals, but it doesn’t have a full picture of that demand because of missing data.

Since 2010, the Water Use Act of 1983 requires annual water usage reports for “all high-capacity wells or intakes pumping 70 gallons per minute or more (100,000 gallons/day).” Systems of wells and intakes that have a combined pumping rate of 70 gallons per minute or greater also fall under the requirement.

Those high-capacity entities include public water suppliers like municipalities, industrial-commercial facilities, wildlife and recreation operations and agriculture irrigators.

Multiple sources told Capitol News Illinois that enforcement of reporting requirements across the state is lax.

“We are not a government agency, you know, we cannot really enforce the industries, farmers to report water use every year to us,” said Zhenxing “Jason” Zhang, a principal research scientist at the Water Survey who leads state and regional water supply planning. “We don’t get 100% compliance.”

Water use reporting is key to understanding what the state will need in the future and how to plan for it, he said. Without that information, resource planning is more difficult.

Management and planning

Nora Beck, an employee at the Chicago Metropolitan Agency for Planning, or CMAP, said the state needs to update its rules about who’s in charge of water resources so the state can better manage them.

“Everything legislative has been sort of piecemeal over time,” she said.

CMAP does water supply planning for northeast Illinois, where many supply issues exist because people outside of Chicago and its immediate suburbs rely on hard-to-replenish aquifers where water levels have dropped dramatically.

A 2018 report from the Water Survey, for example, projected Joliet would be unable to meet water demands by 2030 if it continued using the aquifer, so the city is in the process of moving to Lake Michigan as a source.

Illinois has a limit for how much water it’s allowed to draw from the lake because of the Great Lakes–St. Lawrence River Basin Water Resources Compact — an agreement between eight states and two Canadian provinces concerning water quality and withdrawals from the Great Lakes. That limit doesn’t exist for groundwater, Beck said.

Beck said approximately 80% of the people CMAP serves rely on Lake Michigan for water, but the rest rely on groundwater sources.

“We have a water budget, basically, for the Lake Michigan properties,” she said. “The remaining 20% are mostly on groundwater sources where there’s not a clear budget. Any user can pump as much as they want.”

Ventura, the senator from Joliet, has been involved in water policy since she worked as a naturalist for Georgia State Parks and Historic Sites.

She said looking at each water region in Illinois separately and streamlining oversight authority would be smart approaches to management. Ventura also suggested the state should mimic the Great Lakes Water Compact to create water use agreements across Illinois.

“Having that regional study is still really important,” Ventura said. “And then looking at things like refilling aquifers or having a long-term plan for access to water, I think is important for everyone in our state.”

There’s no single agency that manages water use in Illinois, either, she said. The IDNR, IEPA and the Illinois Department of Agriculture all manage water to different degrees, and with different focuses.

Of the three agencies, the IDNR shoulders the most responsibility for water supply and works with groups like CMAP, the State Water Plan Task Force and the Water Survey to do regional planning and monitoring. But at a February hearing on groundwater, a representative from the IDNR said the agency faces serious staffing shortages that limit its ability to monitor usage and enforce reporting.

Since 2024, CMAP has worked with IDNR, Illinois-Indiana Sea Grant and the Northwest Water Planning Alliance to develop a water sustainability plan for five counties in northeastern Illinois. Beck said a statewide version of that could be helpful.

Beck has also discussed governance strategies with Freshwater Society, a Minnesota initiative to better manage drinking water. Minnesota is currently developing updated rules for groundwater governance.

“I don’t think we need to copy directly from another state,” Beck said. “But I think it’s important to note that these other states are recognizing that they need to upgrade their groundwater governance, and they’re improving it in ways.”

Other solutions

Ventura has introduced or cosponsored legislation to give the Illinois Department of Agriculture more authority over some withdrawals, and a bill to put more restrictions on private companies buying water from municipalities. But those measures have stalled.

She also has a data center regulation bill that would require the facilities to file water use reports and monitor discharged water for pollutants, a provision that could become part of a broader data center regulatory bill.

The POWER Act, a widely debated data center regulatory bill, has several water-related provisions, including requirements for usage, efficiency and water quality monitoring.

“We are looking at, you know, hundreds, thousands, millions of people who need access to water and what that looks like for the future as we move into things like data centers and other climate concerns,” Ventura said.

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.