The Mahomet Aquifer

A Critical Community Resource for Clean Water

The Mahomet Aquifer is the primary source of drinking water for municipalities and homeowners in 14 Illinois Counties. It is the sole source of water for residents of the Cities of Champaign, Urbana, and Savoy, as well as other central Illinois communities. The aquifer provides drinking water to hundreds of thousands of people. The aquifer also supports thousands of commercial, industrial, and agricultural water users. The City believes that preserving this source of clean water that is vital to all of our residents, as well as to agriculture and industry, is in the best interest of the community. To that end, the City has partnered with other communities and affected parties including Champaign County and DeWitt County; the cities of Urbana, Delavan, Clinton, Watseka, and Gilman; the Town of Normal; the Villages of Armington, Savoy, Mahomet, Mansfield, and Waynesville; the University of Illinois; and the Illinois American Water Company to protect this vital resource. This group submitted an application to the U.S. EPA on December 12, 2012, to have the Aquifer designated a Sole Source Aquifer (SSA).

Why Support U.S. EPA Sole Source Designation for the Mahomet Aquifer?

The Mahomet Aquifer is a vital source of water for central Illinois, providing the primary source of clean water to residents of 14 Illinois Counties. The Aquifer is vulnerable to contamination and needs to be preserved for future generations. SSA designation can provide additional federal protection of the Aquifer. Protecting the aquifer also supports agriculture and industry. Please review the attached “fact sheet” for more information. Why support U.S. EPA sole source designation for the Mahomet Aquifer?

Layne Hydro Report – Phase 1: Determining the Mahomet Aquifer’s Eligibility for Sole Source Designation

The City and other partners contracted with Layne Hydro to prepare a report on the Mahomet Aquifer’s eligibility for sole source designation.

Layne Hydro Report- Phase 2: Petition to Designate the Mahomet Aquifer as a Sole Source Aquifer

On December 12, 2012, a coalition of agencies submitted their application to the U.S. Environmental Protection Agency (U.S. EPA) for sole source designation for the Mahomet Aquifer.  The Mahomet Aquifer provides nearly 100% of the drinking water for this region and supports thousands of commercial, industrial, and agricultural water users. Review of this petition by the Region 5 office of the U.S. EPA is expected to take at least six months.  During the review process, the coalition will continue to solicit public input and provide additional information to the U.S. EPA. Copy of Petition for Mahomet Aquifer Sole Source Designation filed on Behalf of the Coalition Some of the large files including maps are not available if you would like an electronic copy of these please send an email to Joseph Hooker- or call 217.403.8765.

More Information on U.S. EPA Sole Source Aquifer Designation

Please see the Q & A for details on sole source designation including answers to the following questions –

  • Why is the Mahomet Aquifer important and why should it be designated as a “sole source aquifer?”
  • What is a sole source aquifer?
  • How many communities consider the Mahomet Aquifer their sole source of water?
  • Can the public participate in the U.S. EPA’s designation process?
  • What happens after an aquifer is designated?

Complaint Filed with Illinois Pollution Control Board (IPCB) to Prevent the Operation of a Chemical Waste Landfill over the Aquifer

On November 9, 2012, the City, on behalf of a coalition of local government agencies, including the Cities of Urbana, Bloomington and Decatur, the Town of Normal, the Village of Savoy, Champaign County and Piatt County, and the Mahomet Valley Water Authority, filed a Complaint with the IPCB seeking to have the IPCB order Clinton Landfill, Inc. a subsidiary of Peoria Disposal Company (PDC) and Area Disposal Services, Inc. (Area), to cease its operation of a chemical waste unit at its landfill facility outside of Clinton, Illinois. The facility is located directly over the Mahomet Aquifer. The Complaint asserts that the chemical waste unit was never lawfully authorized because of the Landfill Company’s failure to get local siting approval from the DeWitt County Board as is required by the Illinois Environmental Protection Act. The Illinois Attorney General agreed with the coalition’s legal position and filed a brief on behalf of the People of the State of Illinois in favor of the Complaint. That Complaint was dismissed by the IPCB on September 19, 2013, based on the fact that the Illinois EPA had granted a modification to the Landfill’s original municipal waste landfill permit that purported to authorize operation of the chemical waste unit. Remarkably, the IPCB conceded in its written decision that the IEPA may not have followed State law when it issued the permit modification without requiring the Landfill company to first obtain local siting approval by the DeWitt County Board. Nevertheless, the IPCB concluded that the Landfill company was entitled to rely on that questionable permit modification to operate the facility. The coalition partners are currently evaluating the best course of action to challenge this decision, which defies common sense and completely undermines the integrity of the local siting review process. To review any of the documents filed with the IPCB in this matter, go to the IPCB website and enter the case number, PCB 2013-022. For questions regarding the IPCB Complaint and the coalition’s next legal actions, please call Assistant City Attorney Joe Hooker with the City’s Legal Department at 217.403.8765, or contact him at

Public Hearings and Comment Period for EPA to Determine Proposed Sole Source Aquifer Designation

CHICAGO (March 12, 2014) – The U.S. Environmental Protection Agency today proposed approval of a petition to designate a portion of the Mahomet Aquifer system in east-central Illinois as a sole source aquifer. EPA’s public comment period on the proposed designation begins March 13 and closes June 12, 2014. The Safe Drinking Water Act gives EPA authority to designate an aquifer as a sole or principal source of drinking water for a specified area. That designation allows EPA to review all federally funded projects within the designated area to ensure they will not contaminate the aquifer. The Mahomet Aquifer system is an underground layer of water-bearing sand and gravel that fills a wide bedrock valley in all or parts of 14 east-central Illinois counties. The aquifer system is the source of approximately 53 million gallons of water every year for 120 public water systems and thousands of rural wells that serve about a half million people. More than half of the population in east-central Illinois relies on the Mahomet Aquifer system as a source of the drinking water. EPA will hold two public hearings on May 13 at 7:30 p.m. at the Hilton Garden Inn, 1501 S. Neil St., Champaign; and on May 14 at 7:30 p.m. at the Best Western Ashland House Hotel at 201 East Ashland Street, Morton. Oral and written comments will be accepted at both hearings. Informational sessions in advance of the public hearings will run from 6:30 p.m. to 7:15 p.m. on both evenings. Draft documents and information about the public hearings are available on EPA’s website at Documents are also available at:

  • 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.
  • Watseka Public Library, 201 S. 4th St., Watseka.
  • U.S. EPA’s Region 5 Office, 77 W. Jackson Blvd., Chicago.

Comments should be addressed to William Spaulding, U.S. EPA (WG-15J), 77 W. Jackson Blvd., Chicago, IL 60604-3590 or For questions or additional information contact William Spaulding at 312-886-9262, or EPA’s toll-free line at 800-621-8431, 9:30 a.m. to 4:30 p.m. (weekdays).

Mahomet Aquifer Summit Videos

The Mahomet Aquifer Summit was held in the Town of Normal on February 22, 2014.  Below are videos taken of the Summit. Videos provided by the Town of Normal. Video 1 Video 2 Video 3