What is a Combined Sewer Overflow or CSO?

Fort Wayne, New Haven and over 100 other communities in Indiana collect both rainwater runoff and sanitary wastewater in the same set of sewer pipes. These are called combined sewers. Sometimes when it rains, combined sewers do not have enough capacity to carry all the rainwater and wastewater or the Water Pollution Control Plant cannot accept all of the combined flow. In this situation, the combined wastewater overflows from the collection system into the nearest body of water, creating a combined sewer overflow or CSO. The main pollutants on CSOs are untreated human waste, toxic materials like oil and pesticides and floating debris that may wash into the sewer system. These pollutants can affect your health if you come into contact with CSO-polluted water or if you eat fish from waters polluted by a CSO.

How are CSOs Controlled?

The Clean Water Act requires the US Environmental Protection Agency (EPA) and the Indiana Department of Environmental Management (IDEM) to issue permits with requirements for controlling discharges from CSOs. The cities of Fort Wayne and New Haven in Allen County are responsible for implementing a series of minimum CSO controls and developing and implementing a long-term CSO control plan to protect water quality. The minimum CSO controls require communities to; (1) maximize the use of the sewer collection system, (2) reduce the amount of pollutants entering the combined sewers and (3) control as much solid and floatable matter as possible from the CSOs. Fort Wayne and New Haven have both developed long term control plans to identify, evaluate and implement various control strategies and achieve various water quality standards. Some of these controls include increased sewer capacity for storage, increased capacity a the Water Pollution Control Plant to treat more combined sewage and mechanisms to treat flow at the point where it enters the river.

CSO Notification

If you would like to be notified of a combined sewer overflow event, sign up for the CSO Notification List. You will be notified when a CSO even has occurred or is expected to occur. Please note that during a CSO event special caution should be taken to avoid contact with the listed affected waters.

To sign up for Fort Wayne's list visit the City of Fort Wayne CSO list signup page.

Here is the ACPWQ CSO Brochure.