Pretreatment is the regulating of commercial and industrial sewage facilities that discharge wastewater to publicly owned treatment works. All pretreatment programs are mandated under the federal Clean Water Act and U.S. EPA has delegated the program to Ohio for implementation. At Ohio EPA, the Pretreatment Unit is responsible for implementing the pretreatment program. Since local sewer control is best handled at the local level, Ohio EPA delegates program responsibilities to local governments, but also directly regulates industries when local government is unable to perform the role effectively or is not mandated to have an approved pretreatment program. The Department of Water Resources (DWR) is responsible for dealing with compliance to regulate those regulations.

All commercial sewer accounts are required to fill out a commercial questionnaire to determine the sewage discharged from their facility.

Any commercial activity requiring pretreatment prior to discharge is required to register with the Department and submit maintenance documentation annually.

To date, the Department has over 580 commercial sewer accounts with over 130 requiring pretreatment of their sewage before being discharged to the County wastewater treatment plants.