Combined Sewer Overflow (CSO)


CSO Location Map

CSO Discharge Info


The City of Metropolis is developing a long-term plan to reduce sewer overflows to the Ohio River, as required by the U.S. Environmental Protection Agency and the Illinois Environmental Protection Agency.

Combined sewer overflows are a century-old problem in more than 700 U.S. communities, particularly in the Northeast and Midwest. Illinois has more than 100 communities with combined sewers, which combine sewage and stormwater into the same pipe.

During dry weather, sewage flows safely through the City's sewers to the Metropolis sewer treatment plant (STP). However, about 50 times a year melting snow or rainwater can overwhelm the sewers, causing untreated sewage to overflow into the Ohio River.

Metropolis must examine its sewer overflows and prepare a long-term control plan that meets Clean Water Act requirements and protects the Ohio River. This City is working with Illinois EPA to develop the plan.

The City of Metropolis has installed signage at the CSO outfall location.  The signs are weatherproof, and will identify the outfall number along with contact information and phone number. 

To be added to the email distribution that is used to notify the public of when the CSO discharges, click HERE.