City agreed to pay $30,000 civil penalty and implement approximately $30 million in sewer system rehabilitation through 2035 to resolve at least 300 documented unpermitted sewage discharges.

City of Cahokia Heights, Illinois — Sanitary Sewer Overflow (2024)

Outcome: City agreed to pay $30,000 civil penalty and implement approximately $30 million in sewer system rehabilitation through 2035 to resolve at least 300 documented unpermitted sewage discharges into local waterways.

The City of Cahokia Heights, a small municipality in southwestern Illinois near St. Louis, operated a sewer collection system that discharged raw and partially treated sewage into local waterways on at least 300 documented occasions between November 2019 and the date of settlement in December 2024. These discharges occurred from sewer cleanouts and other overflow points without National Pollutant Discharge Elimination System (NPDES) permits, in direct violation of Clean Water Act Section 301(a).

The settlement, announced December 10, 2024, was reached between the United States, the State of Illinois, and the city. The consent decree requires Cahokia Heights to implement a two-phased sewer system rehabilitation program stretching through 2035, including infrastructure assessment, pipe cleaning and repair, and a system capacity analysis. The $30,000 civil penalty reflects the city's limited financial resources as a small, lower-income municipality.

The case illustrates a systemic pattern seen in aging Midwest municipalities: deferred infrastructure maintenance leading to chronic overflow conditions that accumulate into federal enforcement actions. The combination of aging clay tile pipes, stormwater infiltration, and inadequate maintenance programs drove the violation record. Federal and state regulators used the consent decree framework to impose a structured, long-term remediation plan rather than simply penalize the city.

Primary Source: Cahokia Heights 2024 Clean Water Act Case Summary | US EPA