State Sen. Chapin Rose, R-Mahomet, said he is drafting a new bill to bar data centers from using Mahomet Aquifer water for cooling and to ban nondisclosure agreements between data center developers and local governments. The new bill aims to address some of the actions the Village of Mahomet took when talking to Clean Cloud Energy about a proposed data center just south of Mahomet.
Rose said he will file the bill in the current General Assembly ahead of the fall veto session, then again in the General Assembly in the spring, if necessary.
On Tuesday night, the Mahomet Board of Trustees approved letters to Rose and state Rep. Chris Miller supporting aquifer protection legislation. The letters urge lawmakers to act during the veto session or in the January lame-duck session.
The Legislative Reference Bureau, which drafts bills for lawmakers, is writing Rose’s measure now. Rose said he expected a first draft this week and that it may need a second or third round of revisions.
The Illinois Senate’s veto session calendar lists session days Nov. 17–19 and Dec. 1–3.
Rose said the bill will include:
Cooling ban, no size limit. A data center won’t be able to draw water from the Aquifer for cooling purposes. Ordinary uses, such as restrooms, would not be affected.
Water from other suppliers. The ban would apply even when another entity draws the water. Asked whether a data center could use aquifer water drawn by someone else, Rose said, “Not for the cooling purposes.” He said the ban would cover both the initial filling of a cooling system and later refills.
Water table safeguards. The bill would add limits on a facility’s overall water use, require studies, and require an immediate shutdown if the water table starts declining. Rose said that even facilities using proprietary cooling systems have lowered nearby water tables over time.
No NDAs. Rose said he will tighten language in the bill to prohibit NDAs between data centers and any unit of government.
Elected officials not bound. An NDA signed by a staff member, such as a Village official, could not bind elected board members. “My new bill is just going to say you can’t bind an elected official,” Rose said, raising free speech concerns.
Extraterritorial jurisdiction. The bill would address what Rose called “venue shopping” between jurisdictions. Champaign County’s moratorium does not reach the Mahomet-area site because it sits in the village’s extraterritorial jurisdiction.
Rose filed SB 4004, the Data Center Water Transparency and Aquifer Protection Act, earlier this year. As introduced, it would have barred data centers from using aquifer water starting Jan. 1, 2027, and given existing facilities until Jan. 1, 2028, to stop. It also barred local governments from NDAs that restrict disclosure of a data center’s water use. The bill was sent to the Senate Executive Committee’s AI and Social Media subcommittee and never received a vote.
“I thought I actually had a pretty good shot to get this thing done by the end of May,” he said.
Lawmakers passed some AI legislation before the session ended but no data center bills, including those filed by Democrats.
Rose said the timing worries him. He argued that guardrails have broad public support, so passing them before the Nov. 3 election would have been an easy win.
The Mahomet Daily asked Rose on Oct. 3 whether he supported the proposed data center near Mahomet, Rose replied by email: “No. I think this is a TERRIBLE idea.” He compared it to the truck stop proposal “that nobody asked for, nor wanted.” He wrote that he had attended a rally against the project that morning.
Rose wrote that he wanted a permanent ban rather than Champaign County’s temporary one. “What was the point of ‘temporary’? he wrote.
The Champaign County Board approved a 12-month moratorium on large data centers on April 23.
Mahomet Trustee Bruce Colravy requested the letter from the Village of Mahomet at the Oct. 13 study session, along with a resolution banning village NDAs and a moratorium similar to Champaign County’s. Only the letter was on Tuesday’s agenda.
The letter approved by the board on Oct. 27 says the village supports legislation to keep data centers from using aquifer groundwater for cooling. It names acceptable alternatives “including, but not limited to, reclaimed water, surface water, or closed-loop or air-cooled systems.” It also backs the requirement of a closed-loop cooling system for data center developments.
“The Mahomet Aquifer is an essential source of drinking water for our community and communities throughout the region,” the letter reads.
At that meeting, Colravy objected that an NDA signed by staff had covered elected officials. According to the minutes, he said “NDA’s should not be signed on the behalf of others.”
The 104th General Assembly ends in early January. Bills that have not passed by then die and must be refiled. Rose said he will file the new measure again in the 105th General Assembly if needed.
The Mahomet Aquifer supplies drinking water to nearly 750,000 people in Central Illinois.