The U.S. Environmental Protection Agency announced a decision to designate a portion of the Mahomet Aquifer system as a sole source aquifer. More than half of the population in east-central Illinois relies on the Mahomet Aquifer system as a source of drinking water.

The Safe Drinking Water Act gives EPA authority to designate all or part of an aquifer as a sole source if contamination of the aquifer would create a significant hazard to public health and there are no physically available or economically feasible alternative sources of drinking water to serve the population that relies on the aquifer. The designation authorizes EPA review of projects that receive federal financial assistance to assess potential for contamination of the aquifer system that would create a significant hazard to public health.

The Mahomet Aquifer system is an underground layer of water-bearing sand and gravel that fills a wide bedrock valley in an area that includes 14 east-central Illinois counties. The aquifer system provides about 58 million gallons of drinking water each day for 120 public water systems and thousands of rural wells that serve about a half million people in Illinois.

EPA’s public comment period on the designation began on March 13, 2014, and closed on June 12, 2014. The EPA held public hearings on May 13 in Champaign and on May 14 in Morton. Following a review of public comments, the EPA prepared a Responsiveness Summary, which addresses comments and answers questions. The decision goes into effect when it is published in the Federal Register.

The Responsiveness Summary and other relevant documents will be available to the public at EPA’s regional office, 77 W. Jackson Blvd., Chicago; Champaign Public Library, 200 W. Green St., Champaign; Bloomington Public Library, 205 E. Olive St., Bloomington; Pekin Public Library, 301 S. Fourth St., Pekin; Havana Public Library, 201 W. Adams St., Havana; and Watseka Public Library, 201 S. 4th St., Watseka.

For more information, go to www.epa.gov/region5/water/gwdw/mahomet.