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8/19/2022 1:23PM
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Combined Sewer Overflow

What is a Combined Sewer Overflow

Combined Sewer Overflows (CSO's) are common in cities the age of Newark. Sewers in Newark originally were just ditches or large pipes that took household sewage to the river. In the 1940's, Newarks first sewer plant was built and in the following years sewer pipes were tied into a system that ended at the wastewater treatment plant. Some pipes were left as a pressure outlet to the river in times when heavy rainfall resulted in higher than normal pressures developing in the sewer pipes that would result in backups into homes. To prevent backups these pipes were left as a pressure release to prevent all but the most extreme rainfalls causing backups into homes.  The Ohio EPA under direction from US EPA have mandated that all CSO's be removed. This page contains information on the locations and plans to remove these CSO's from the system. Current laws require the removal of these CSO's to the river by using construction to increase the capacity of the sewer system to accept rainfall events. Current and future construction will be listed on this page until all CSO's in the City of Newark are removed. Information concerning health concerns and rainfall events will also be listed on this page.

Predicting Wet Weather Sewer Overflows

At this time, Newark does not have a fail-safe method for predicting or monitoring combined sewer overflows on a real-time basis. There are many factors that can trigger overflows, including the length and intensity of rainfall, prior ground moisture conditions, sewer blockages, etc. The methods for predicting CSO overflows are expected to improve as Newark implements it's Long-Term Control Plan Update. In the meantime, Newark will issue a CSO warning whenever its weather forecasting service predicts or records a rainfall of .25 inches or more in Licking County or whenever the water levels in area rivers and streams are elevated such that a CSO overflow is likely to occur. The warning will remain in place for 72 hours after a rainfall occurs and 72 hours after water levels in area rivers and streams have returned to normal elevation and CSO discharges related to elevated river and stream levels are known or believed to have ceased in Licking County.

To view a CSO Interactive Map (locations of CSO's in Newark) or to recieve an E-mail notification of CSO events please click on the link below.

Interactive CSO Map

City of Newark Long Term Control Plan

The City of Newark Long Term Control Plan was established in September of 1998.  To view a copy of the Long Term Control Plan click on the links below.

Long Term Control Plan

Long Term Control Plan Appendices

The Process of Eliminating Combined Sewer Overflows

As part of the City of Newark Long Term Control Plan, three construction projects have been completed which allow the City to eliminate or decreases flow from its CSO’s.  The first project separated the combined sewer lines and eliminated CSO 1007 at the Everett Ave Bridge.   CSO 1007 was eliminated in 2009.  The second project installed a 48-inch line from CSO 1006 to junction chamber #1.  CSO 1006 was eliminated near Monroe Street in 2011.  The third and largest project and most recent, is the completion of the high rate treatment facility located at the Newark Wastewater Treatment Plant.  The City is now able to treat millions of gallons per day more storm water flow before it enters the Licking River.