What is a Combined Sewer System and Combined Sewer Overflow (CSO)?
According to the United States Environmental Protection Agency (EPA), a “combined sewer system” and “combined sewer overflow” are defined as follows: Combined sewer systems are sewers that are designed to collect rainwater runoff, domestic sewage, and industrial wastewater in the same pipe. Most of the time, combined sewer systems transport all of their wastewater to a sewage treatment plant, where it is treated and then discharged to a water body. During periods of heavy rainfall or snowmelt, however, the wastewater volume in the combined system can exceed the capacity of the sewer system or the treatment plant. For this reason, combined sewer systems are designed to overflow occasionally and discharge excess wastewater directly to nearby streams, rivers, or other waterbodies. These overflows, called combined sewer overflows (CSOs), contain not only stormwater but also untreated wastewater. Does the Owensboro community currently have a combined sewer system and CSOs? Yes. What is the
