Alton District CSO Information

Alton CSO System

In June 2019, Illinois American Water acquired the Alton Regional Wastewater System which serves customers in Alton and nearby communities of Bethalto and Godfrey. Since acquiring the system, the company has been making investments to the sanitary sewer system to upgrade the system and address requirements set forth by the City’s Long-Term Control Plan. Our commitment includes investing over $50 million over 10 years.

Alton CSO System These investments will support system reliability and public health. To date, a significant portion of the investment completed includes the design phase for separating the combined sewer system in the Turner Tract, Piasa Valley and Shields Valley service areas. This project in part helps to address Long-Term Control Plan requirements outlined in Alton’s National Pollution Discharge Elimination System permit.

Long-Term Control Plan

A combined sewer system collects rainwater runoff, domestic sewage, and industrial wastewater into one pipe. Under normal conditions, it transports all of the wastewater it collects to a wastewater treatment plant for treatment, then discharges to a body of water. The volume of wastewater can sometimes exceed the capacity of the combined sewer system or treatment plant (i.e., during heavy rainfall events or snowmelt). When this occurs, untreated stormwater and wastewater, discharges directly to nearby streams, rivers, and other bodies of water. This is an environmental and community concern. Illinois American Water is working to combat this issue in Alton via a long-term control plan. To learn more about the Long-Term Control Plan, please visit the links below.

To view information regarding flooding and rainfall events which have impacted the wastewater system please click here.


To view the latest road closures please click here.