The Mahomet Aquifer

Consent Decree

Read the consent decree in it’s entirety here

Below are detailed key points of the proposed consent decree:
1. Clinton Landfill, Inc. agrees to withdraw its application before the United States Environmental Protection Agency for approval to accept Polychlorinated Biphenyl (PCB) waste regulated by the Federal Toxic Substance Control Act in the chemical waste unit at the Clinton Landfill. They further agree not to seek future approval to dispose of said PCB waste in any landfill facility located anywhere in DeWitt County over the Mahomet Aquifer.

2. Clinton Landfill, Inc. agrees to not accept additional Manufactured Gas Plant (MGP) waste with chemical constituents in concentrations exceeding state regulatory limits for toxicity in the chemical waste unit. They also agree to not seek future permission from any regulatory body to accept such MGP waste at any landfill facility located anywhere in DeWitt County over the Mahomet Aquifer.

3. Clinton Landfill, Inc. agrees to cover the MGP waste already disposed of in the chemical waste unit (pursuant to an earlier Illinois EPA approval) with a 12 inch layer of impermeable clay soils. This is to prevent water and other liquids from other waste subsequently disposed of on top of the MGP waste from leaking into the MGP waste.

4. Clinton Landfill, Inc. agrees to have properly licensed environmental testing professionals test the groundwater at Clinton Landfill for the presence of toxic chemicals commonly found in MGP wastes on a semiannual basis. Tests are to be conducted for the remaining operational life of the chemical waste unit and for the post-closure period of time (under current law a minimum of 30 years) and to provide those test results to the Illinois Environmental Protection Agency (EPA).

5. The State of Illinois, through the Illinois Attorney General’s Office and the Illinois EPA, reserve the right to pursue any future criminal or civil violations related to any future contamination of the environment from the MGP wastes already accepted at Clinton Landfill, and any remedies available under the law, including but not limited to the removal of the waste material causing the contamination.


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.

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

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.

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

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. 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. Draft documents and information about the public hearings are available on EPA’s website at

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