Governor JB Pritzker has signed the Mahomet Aquifer Protection Bill (Senate Bill 1723) into law. The legislation prohibits carbon dioxide sequestration activities in and around the Mahomet Aquifer.

The Mahomet Aquifer supplies drinking water to about 500,000 people across 14 counties in central Illinois. Concerns over the safety of carbon sequestration, where liquified CO₂ is injected deep underground, intensified after a recent leak at a Decatur facility, though not directly impacting the aquifer area. Advocates for the bill argued that even highly regulated projects posed a risk to this irreplaceable resource, which was designated by the EPA as a “sole source aquifer,” meaning no alternative water supply is available if contamination occurs.

The bill drew bipartisan support and passed by wide margins in the Illinois legislature. The law:

• Bans all carbon sequestration activity over, under, or through the Mahomet Aquifer.
• Creates the Mahomet Aquifer Advisory Study Commission to oversee further research and advise the General Assembly on issues and risks related to carbon storage projects in the region.
• Assigns the Prairie Research Institute at the University of Illinois to conduct ongoing studies and submit safety reports on carbon sequestration in the aquifer area through the end of the decade.

“In signing the bill, Governor Pritzker has shown that clean water always was, and always will be, a critical factor to building climate resilience across Illinois,” the Prairie River Network wrote.

The new law takes effect immediately.