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 HSTS rules – effective May 1, 2021
Dwelling Replacement Policy – Board approved 8-12-20
For sewage system contractor information Click Here
For state forms: Sewage Treatment Forms
For general information regarding sewage treatment, visit the Ohio Department of Health Sewage Program home page: ODH Sewage Treatment Homepage
The Mercer County Minor Subdivision Rules / Planning Commission website: Mercer County Planning Commission
HSTS Frequently Asked Questions
