Septic Systems in Ohio

88 counties · ~20% of homes on septic · ~562,231 septic systems

State Regulation Overview

Regulatory Body
Ohio Department of Health
Inspection Required for Sale
No / Varies by county
Nitrogen Reduction Areas
No
Advanced Treatment Areas
Yes

Local health districts issue permits. Sewage Treatment System (STS) rules updated 2015.

Top Counties by Septic Systems

Hamilton County
~19,935 septic homes
Lucas County
~17,251 septic homes
Franklin County
~15,886 septic homes
Butler County
~15,614 septic homes
Cuyahoga County
~15,178 septic homes

All Counties in Ohio

Adams County
27K pop · ~24% septic
Allen County
102K pop · ~15% septic
Ashland County
52K pop · ~20% septic
Ashtabula County
98K pop · ~20% septic
Athens County
62K pop · ~20% septic
Auglaize County
46K pop · ~24% septic
Belmont County
66K pop · ~20% septic
Brown County
44K pop · ~24% septic
Butler County
390K pop · ~10% septic
Carroll County
27K pop · ~24% septic
Champaign County
39K pop · ~24% septic
Clark County
136K pop · ~15% septic
Clermont County
209K pop · ~15% septic
Clinton County
42K pop · ~24% septic
Columbiana County
102K pop · ~15% septic
Coshocton County
37K pop · ~24% septic
Crawford County
42K pop · ~24% septic
Cuyahoga County
1265K pop · ~3% septic
Darke County
52K pop · ~20% septic
Defiance County
38K pop · ~24% septic
Delaware County
214K pop · ~15% septic
Erie County
76K pop · ~20% septic
Fairfield County
159K pop · ~15% septic
Fayette County
29K pop · ~24% septic
Franklin County
1324K pop · ~3% septic
Fulton County
43K pop · ~24% septic
Gallia County
29K pop · ~24% septic
Geauga County
95K pop · ~20% septic
Greene County
168K pop · ~15% septic
Guernsey County
38K pop · ~24% septic
Hamilton County
831K pop · ~6% septic
Hancock County
75K pop · ~20% septic
Hardin County
31K pop · ~24% septic
Harrison County
14K pop · ~28% septic
Henry County
28K pop · ~24% septic
Highland County
43K pop · ~24% septic
Hocking County
28K pop · ~24% septic
Holmes County
44K pop · ~24% septic
Huron County
59K pop · ~20% septic
Jackson County
33K pop · ~24% septic
Jefferson County
65K pop · ~20% septic
Knox County
63K pop · ~20% septic
Lake County
233K pop · ~15% septic
Lawrence County
58K pop · ~20% septic
Licking County
179K pop · ~15% septic
Logan County
46K pop · ~24% septic
Lorain County
313K pop · ~10% septic
Lucas County
431K pop · ~10% septic
Madison County
44K pop · ~24% septic
Mahoning County
229K pop · ~15% septic
Marion County
65K pop · ~20% septic
Medina County
182K pop · ~15% septic
Meigs County
22K pop · ~24% septic
Mercer County
43K pop · ~24% septic
Miami County
109K pop · ~15% septic
Monroe County
13K pop · ~28% septic
Montgomery County
537K pop · ~6% septic
Morgan County
14K pop · ~28% septic
Morrow County
35K pop · ~24% septic
Muskingum County
86K pop · ~20% septic
Noble County
14K pop · ~28% septic
Ottawa County
40K pop · ~24% septic
Paulding County
19K pop · ~24% septic
Perry County
35K pop · ~24% septic
Pickaway County
59K pop · ~20% septic
Pike County
27K pop · ~24% septic
Portage County
162K pop · ~15% septic
Preble County
41K pop · ~24% septic
Putnam County
34K pop · ~24% septic
Richland County
125K pop · ~15% septic
Ross County
77K pop · ~20% septic
Sandusky County
59K pop · ~20% septic
Scioto County
74K pop · ~20% septic
Seneca County
55K pop · ~20% septic
Shelby County
48K pop · ~24% septic
Stark County
375K pop · ~10% septic
Summit County
540K pop · ~6% septic
Trumbull County
202K pop · ~15% septic
Tuscarawas County
93K pop · ~20% septic
Union County
63K pop · ~20% septic
Van Wert County
29K pop · ~24% septic
Vinton County
13K pop · ~28% septic
Warren County
242K pop · ~15% septic
Washington County
60K pop · ~20% septic
Wayne County
117K pop · ~15% septic
Williams County
37K pop · ~24% septic
Wood County
132K pop · ~15% septic
Wyandot County
22K pop · ~24% septic

Septic Systems in Ohio

Approximately 20% of homes in Ohio rely on septic systems for wastewater treatment, totaling an estimated 562,231 septic systems across the state's 88 counties. This places Ohio among the states with significant decentralized wastewater infrastructure.

Septic Regulations in Ohio

Septic regulations in Ohio are administered by Ohio Department of Health, with permits typically issued at the county level through local health departments. Requirements for tank sizes, setback distances, approved system types, and inspections can vary significantly between counties.

While Ohio does not have a statewide mandate for septic inspections at the time of property sale, individual counties may impose their own requirements. It is common practice for buyers to request a septic inspection as part of their due diligence, even when not legally required.

Common Septic System Types

Homeowners in Ohio typically use one of several septic system types depending on local soil conditions: conventional gravity-fed systems where soil percolation is adequate, pressure distribution systems in areas with moderate limitations, mound systems where shallow bedrock or high water tables prevent conventional installation, and aerobic treatment units (ATUs) in environmentally sensitive areas.

Septic Maintenance Requirements

The EPA recommends pumping septic tanks every 3 to 5 years, though the exact frequency depends on tank size, household size, and water usage. In Ohio, some counties have adopted mandatory pumping schedules or maintenance tracking programs. Proper maintenance prevents costly repairs, protects groundwater quality, and extends the lifespan of the drainfield — the most expensive component to replace.

Select a county above to view detailed septic regulations, estimated costs, soil suitability data sourced from the USDA NRCS Soil Survey, and groundwater depth measurements from the USGS.

Data last updated: 2026-04-13