Combined Sewer Overflow

A CSO is a Combined Sewer Overflow. In a combined sewer system, stormwater and sanitary sewage from domestic, commercial, and industrial sources flow together in a single pipe to the Water Reclamation Facility to be treated.

During rainfall events, the pipes become full of stormwater and sewage. CSO outfalls allow excess flow to discharge to nearby water bodies, preventing backups at storm drains and in basements.

The City of Akron currently has 34 CSO outfalls in the sewer collection system.

  • During wet weather, untreated wastewater discharges to the receiving streams along with large quantities of stormwater.
  • During wet weather the following types of contaminates may be present in the receiving waters: pathogens, bacteria, oxygen-demanding pollutants, suspended solids, nutrients, toxics and floatable matter.

CSOs Outside of Akron

Akron isn't the only city that is being required to upgrade its sewer system to meet EPA water quality standards. Akron is just one of 772 cities across the country with combined sewer overflows, according to the EPA. More information about CSOs across the State of Ohio can be found at the Ohio EPA's website.