Household Sewage Treatment Systems

Household sewage treatment systems are regulated under the authority of Chapter 3718 of the Ohio Revised Code and Chapter 3701-29 of the Ohio Administrative Code.

This program covers septic system siting, building lot approvals, septic system permitting, review of system operation and maintenance, and nuisance investigations. Regulations governing septic systems require soil evaluations on any new building lot, prior to existing system replacement, and at the time of minor subdivision parcel split-offs. Septic system types and sizes are determined by the type and condition of soil found on the individual properties.

Mercer County Sewage Treatment Regulations (eff. Nov . 30, 2015)

For state forms, such as contractor bonds, statewide list of registered contractors and service providers, and general information regarding sewage treatment, visit the Ohio Department of Health Sewage Program home page:

The Mercer County Minor Subdivision Rules / Planning Commission website:

2015 Soil Evaluators

2015 Contractor List

Septic Tank Cleaner List

Service Provider List

Frequently Asked Questions

Permit Process Instructions