EPA - U.S. Environmental Protection Agency

12/10/2024 | Press release | Distributed by Public on 12/10/2024 15:11

Consent Decree and Complaint (Cahokia Heights 2024 Clean Water Act Case Summary)

On December 10, 2024, the Environmental Protection Agency (EPA), Department of Justice (DOJ), and the state of Illinois announced a settlement agreement with the city of Cahokia Heights, IL. The settlement resolves violations of the federal Clean Water Act (CWA) and the Illinois Environmental Protection Act resulting from the city's failure to properly operate its sanitary sewer system. The settlement requires that Cahokia Heights pay a $30,000 civil penalty and implement an estimated $30 million in extensive compliance measures.

Settlement Resources
On this page:

Overview of Cahokia Heights, IL Sewer Collection System

Cahokia Heights has owned and operated the city's separate sanitary sewer collection system since the city's formation and the dissolution of Commonfields in May 2021. Prior to the formation of Cahokia Heights, various parts of what is now the Cahokia Heights sewer system were operated by the city of Alorton, the village of Cahokia, and by Commonfields. Cahokia Heights' sewer system extends over approximately 16 square miles and serves approximately 21,000 residents. It consists of approximately 90 miles of gravity sewers, four miles of force mains, over 2,000 manholes, and 69 lift stations. Cahokia Heights does not have a discharge permit by the EPA or an authorized state under the Clean Water Act.

Summary of the Violations

The complaint against Cahokia Heights alleges that on at least 270 occasions since November 2019, Cahokia Heights discharged sanitary sewage to navigable water in violation of section 301 of the Clean Water Act. Additionally, the city is alleged to have discharged pollutants into waters of the United States without a national pollutant discharge elimination system (NPDES) permit issued pursuant to CWA section 402. Cahokia Heights also discharged untreated sewage from a cleanout in its sewer system and other locations.

The discharges of sanitary sewage constitute a violation of the Illinois Environmental Protection Act and its implementing regulations. Some of the discharges to waters of the state are also alleged to be caused by Cahokia Heights' failure to operate and maintain the sewer system, which is required by state regulation.

Summary of Environmental and Health Impacts

Discharges of raw sewage, or sanitary sewer overflows, carry bacteria, viruses, and other harmful organisms. Sanitary sewer overflows may cause diseases ranging in severity from mild gastroenteritis to life-threatening ailments, such as cholera, dysentery, and severe gastroenteritis. People may be exposed through:

  • Direct contact in areas of high public access such as basements, lawns or streets, or waters used for recreation. At least one study has estimated a direct relationship between gastrointestinal illness contracted while swimming and bacteria levels in the water.
  • Of particular concern here is that with the frequent mixture of standing floodwater contaminated by raw sewage, the city's drinking water distribution system is exposed to contaminated water, which can enter the drinking water pipes when there is a loss of pressure.

Sanitary sewer overflows can also damage property and harm water quality when they enter waterbodies.

Summary of Environmental Benefits

The rehabilitation of Cahokia Heights' sanitary sewer system is expected to substantially reduce the number of sanitary sewer overflows in the community, thereby resulting in a direct and immediate but unquantifiable environmental benefit.

Overview of Consent Decree

The proposed consent decree requires Cahokia Heights to reduce the number of sanitary sewer overflows from its sewer system by

  • Evaluating the condition and hydrologic capacity of its sanitary sewer, and
  • Implementing various measures that will require frequent cleaning and repair to maintain the sewers in good working order and to increase the capacity of the sewer system.

The following is an overview of the work the city must perform:

Phase 1:

  • The city is required to begin the systematic cleaning of the entire sewer system and to develop and implement a Wet Weather SSO Investigation Plan for a portion of the sanitary sewer system to determine the sources and causes of the city's ongoing wet weather sanitary sewer overflows.
  • By September 2029, Cahokia Heights is required to prepare a Sewer Condition Assessment Report describing in detail the deficiencies discovered during the condition assessment.
  • By December 2029, the city must complete a Phase 1 Sewer Rehabilitation Plan, which will require the city to repair or replace sewer lines and defective manholes. The rehabilitation plan must be implemented pursuant to a schedule to be developed by the parties.

After completing Phase 1, the city is required to determine whether it continues to experience capacity related sanitary sewer overflows. If capacity related sanitary sewer overflows remain a problem, then the city is required to prepare a Capacity Analysis Alternatives Plan.

Phase 2:

  • Cahokia Heights is required to investigate areas of the sanitary sewer system not evaluated in Phase I to determine the condition for the remainder of the sewer system and prepare a Sewer Condition Assessment Report, as well as a Sewer Rehabilitation Plan describing the corrective measures to repair the additional sewer system defects by December 2035.

Under the proposed consent decree, Cahokia Heights will conduct more than 80 near-term capital improvement projects, such as constructing an interceptor to re-route wastewater flow, system-wide repairs and various investigations and assessments. The city is also required to keep the community informed about the work, have plans in place for emergencies, and update its operations such as creating digital maps and monitoring in real-time known overflow points.

Comment Period

The proposed consent decree was lodged in the U.S. District Court for the Southern District of Illinois on December 10, 2024. The consent decree is subject to a 60-day comment period. Information on how to provide comments and a copy of the proposed consent decree are available on the Justice Department's Propose Consent Decree webpage. 

Contact Information

For additional information on this settlement, please contact:

Deborah Carlson, Attorney
Region 5
Office of Regional Counsel
Ralph H. Metcalfe Federal Building
77 West Jackson Blvd.
Chicago, IL 60604
(312) 353-6121

James Vinch, Attorney Advisor
Water Enforcement Division
Office of Enforcement and Compliance Assurance
1200 Pennsylvania Avenue, NW
Washington, D.C. 20460
(202) 564-1256