Building permits, zoning and septic rules in Franklin County, Ohio

Unincorporated Franklin County, Ohio requires a building permit for new and modular houses, interior alterations, detached garages or pole barns, decks, pools, porches, demolition, and accessory structures larger than 200 square feet¹. The county directs applicants to the 2019 Residential Code of Ohio for its building code¹. Permits for properties with public water and sewer are issued 7 to 10 days after full plan approval². For a property with a private well or cistern, Franklin County Public Health reviews the plans before returning them to the Building Department². Electrical, heating, plumbing, well, and septic work each require separate permits¹. An owner who does the electrical, heating, plumbing, well or septic work personally may obtain a homeowner's permit after signing an affidavit to that effect; the separate trade permits are still required¹. Like most counties around it in Ohio, Franklin County requires a county building permit¹. In Columbus, the city building official issues building permits; Columbus Public Health handles household sewage treatment systems within its jurisdiction^8,9.

The Franklin County Building Department handles covered building work in unincorporated Franklin County^1,2. Reach the office at 142 S. Front St., Columbus, Ohio, 43215, by phone at 614-525-3166, or by email at building@franklincountyohio.gov². Apply in person or online². Planning questions go to planning@franklincountyohio.gov at the same phone and street address². County zoning applications carry an application fee, while building-review and inspection fees follow the locally adopted schedule^10,11.

Franklin County zoning applies to unincorporated territory except where a township zoning resolution applies or the county resolution has been repealed^3,5. Brown, Clinton, Franklin, Hamilton, Madison, Mifflin, Norwich, Pleasant, Sharon, and Truro Townships submit zoning-compliance applications to the county Economic Development and Planning Department². Blendon, Jackson, Jefferson, Perry, Plain, Prairie, and Washington Townships use their own zoning authorities, as do the villages listed on the county building-permit page². Inside the cities, Reynoldsburg administers zoning through its Planning and Zoning Division¹², and Westerville zones its own land¹³. Septic systems outside Columbus stay with Franklin County Public Health within its health-district jurisdiction⁴. County-administered districts set permitted uses and development standards, so identify the district before planning a house⁵. The county Limited Suburban Residential District requires at least 20,000 square feet per dwelling unit and centralized water and sanitary sewer service; that standard is not a countywide minimum for every residential parcel⁵.

Franklin County Public Health reviews, inspects, and regulates household sewage treatment systems within its health-district jurisdiction⁴. Installing, repairing, or replacing a septic system requires a separate permit¹. Ohio's process requires a site review that generally includes a soil evaluation and system design before the health board issues an installation or alteration permit; operating the system also requires a valid operation permit¹⁴. Franklin County Public Health makes annual observations of aeration systems, evapotranspiration mounds, commercial systems, and household systems installed since 2015⁴. USDA rates 0% of the county's soils as not limited for a conventional drain field, so expect a site evaluation and possibly an engineered system rather than a standard trench¹⁵. Franklin County Public Health also permits construction, alteration, and abandonment of private water systems, including wells, cisterns, springs, ponds, and hauled-water tanks⁴.

In unincorporated Franklin County areas governed by county zoning, recreational vehicles and camping trailers cannot be used for living, sleeping, or housekeeping on residential property outside an approved recreational park or campground^5,6. RV parking and storage are regulated separately; permission to store an RV does not authorize living in it⁶. Ask the township zoning authority about parcels under separate township zoning². We could not confirm a tiny-home occupancy rule in the county zoning resolution; ask the county Economic Development and Planning Department or the parcel’s township zoning authority². New manufactured homes in the county-administered Residential Manufactured Home overlay district must have at least 900 square feet of living area, excluding garages, porches, and attachments, and be at least 14 feet wide at one point⁵. That district also requires a permanent foundation, appropriate utilities, and frontage on an approved subdivision street, with no lot access to an existing township, county, or state road⁵. A regulated manufactured home generally cannot be occupied until a state inspector issues the inspection seal¹⁶.

1. Identify the parcel’s zoning authority and district, and obtain the applicable zoning-compliance documentation^2,5.
2. For private septic or water, begin with Franklin County Public Health; septic and well work require separate permits^1,4.
3. Submit the building-permit application to the Franklin County Building Department in person or online².
4. Allow for plan review: public-water-and-sewer properties receive building permits 7 to 10 days after full plan approval, while private-well or cistern plans first need Franklin County Public Health approval².
5. Arrange building inspections as work progresses; Ohio building officials inspect against approved construction documents¹⁷. Hot tubs, spas, and swimming pools need electrical bonding inspections; for an inground pool, bonding inspection must precede footing inspection¹.

Confirm the zoning authority and district before making an offer because Franklin County and local jurisdictions divide zoning work^3,5. Check the soil before counting on a conventional septic field: USDA data rates 0% of assessed county soils as free of severe limitations for that use¹⁵. If an existing septic system discharges to the county storm-sewer system, Franklin County Public Health works with the owner to connect to an available sanitary sewer or install an approved septic system⁴. A lot split can create up to 4 new lots smaller than 5 acres, while large-lot development covers 5-to-20-acre lots and a major subdivision begins at 5 new lots or when another category does not fit⁷. Franklin County's density is about 2,491 people per square mile, and the nearest city of 100,000 or more is about 2 miles from the county center¹⁵. The median annual property-tax bill is about $4,110, with an effective rate near 1.5%¹⁵.