Utilities Department

Background

The City of Lima has nearly 250 miles of sanitary sewer lines that convey wastewater to the treatment plant. Approximately 60% of these sewers are considered combined sewers, which simply means that one pipe out in the street conveys all wastewater and storm water to the Wastewater Treatment Plant. The other 40% are considered separated sewers, which means that there are two separate pipes in the street – one carries only sanitary waste to the treatment plant, and the other carries only storm water to a nearby drainage ditch or river.

What is a Combined Sewer Overflow (CSO)?

The Combined Sewer system can become overloaded during extremely heavy rainfall events. The system has built-in relief points that are designed to release the extra flow of combined sewage and storm water to area waterways to prevent basement flooding. When this happens, it becomes a recordable Combined Sewer Overflow and must be reported to the Ohio Environmental Protection Agency.

Because CSOs are a mixture of storm water and sewage, pollutants are discharged to area waterways during overflow events.  To avoid any possible health effects from a sewer overflow, please avoid contact with the water near a CSO discharge location, particularly after a rain storm. This includes activities such as boating, wading, fishing and swimming. Signs are posted along the local waterways identifying sewer discharge locations. For more information on possible health and environmental impacts of overflows, please visit the following U.S. EPA web site. http://cfpub.epa.gov/npdes/cso/cpolicy_report2004.cfm


Location & Frequency of CSOs

The City of Lima has 19 permitted CSOs in its National Pollution Discharge Elimination System (NPDES) permit where overflow can discharge to a nearby stream. Of the 19 CSOs, 13 discharge to the Ottawa River and the other 6 discharge to Pike Run Ditch on the City's North side.

Click here to see the location of CSOs in the Lima Sewer District.

Five of the CSOs are major structures located on the Ottawa River and are monitored continuously using state-of-the-art electronics. The remaining CSOs are monitored manually after a rainfall event of 0.25 inches or greater.
Click here to see the most up-to-date overflow activity.