Franklin County, OH zoning map, flood zone and property lines by address
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Towns in Franklin County: Columbus, Dublin, Grove City.
Flood zone by address
ParcelSheet reads FEMA's National Flood Hazard Layer at the lot: the zone, whether it is a high risk area where lenders ask for flood insurance, and the base flood elevation where FEMA lists one. FEMA's countywide study for Franklin County has 177 FIRM panels, the newest effective June 2011; no coastal V zones are mapped in it.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for a Franklin house comes from a licensed surveyor and is often on file with the county or city building office.
Property lines
The parcel outline, parcel number and mapped size come from the Ohio statewide parcel layer (OGRIP, Ohio Department of Natural Resources, from each county auditor), so a Franklin lot shows the same lines the county auditor draws. Franklin County covers about 340,757 acres of land and 7,161 acres of water.
Mapped lines are approximate. The Franklin County auditor keeps the parcel record (Franklin County website); a licensed surveyor sets the true corners.
Zoning
In Ohio zoning is set by the county, the township or the city or village, depending on where the lot is: in Franklin County, Columbus, Dublin, Grove City each zone the land inside their limits. ParcelSheet shows the use code on the lot's parcel record and the municipality it sits in; the county, township or city zoning office has the district, the uses it allows and the lot size it needs. The Franklin County website lists the county's municipalities.
ADU and guest houses
Under Ohio's zoning laws (Ohio Revised Code chapters 303, 519 and 713), the county, the township or the city or village, depending on where the lot is can allow an accessory dwelling unit on a lot with a house. Whether a Franklin lot can add one depends on its district; the county, township or city zoning office has the rule. ParcelSheet shows the mapped lot size and the ground's slope, the first two things the question turns on.
Septic and soil
ParcelSheet reads the USDA soil survey at the lot: the soil's name, its septic absorption rating and whether it is prime farmland. Franklin County is soil survey area OH049, Franklin County, Ohio, last updated September 2026, on Web Soil Survey.
A new or changed septic system in Franklin County needs a permit from the Franklin County local health district under the Ohio sewage treatment system rules (Ohio Administrative Code 3701-29).
Setbacks
Setbacks in Franklin County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the county, township or city zoning office gives them for the lot's district, and Columbus, Dublin, Grove City for land inside their limits.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a Franklin lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Franklin County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA's countywide flood map for Franklin County has 177 panels, the newest effective June 2011. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Franklin County?
Open the Ohio map, type the address, and the parcel outline from the Franklin County auditor shows on the map with its parcel number and mapped size. Mapped lines are approximate; only a licensed surveyor sets the true corners.
What is my property zoned in Franklin County?
Zoning in Franklin County is set by the county, the township or the city or village, depending on where the lot is (such as Columbus, Dublin). ParcelSheet shows the use code on the parcel record and names the municipality; the county, township or city zoning office has the final word.
Can I build an ADU in Franklin County?
Under Ohio's zoning laws (Ohio Revised Code chapters 303, 519 and 713), the county, the township or the city or village, depending on where the lot is can allow an accessory dwelling unit, and each sets its own rules. In Franklin County ask the county, township or city zoning office for the lot's district first; ParcelSheet shows the lot size as mapped so you can see the room you have.
Do I need a septic permit in Franklin County?
Yes. A new or changed septic system in Franklin County needs a permit from the Franklin County local health district under the Ohio sewage treatment system rules (Ohio Administrative Code 3701-29). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area OH049 (Franklin County, Ohio).
What can I build on 5 acres in Franklin County?
Zoning in Franklin County is set by the county, the township or the city or village, depending on where the lot is (such as Columbus, Dublin). The zoning district decides the uses, how many homes and the smallest lot it allows on 5 acres. ParcelSheet shows the lot size as mapped and the use code on the parcel record; the county, township or city zoning office has the district and its rules. See the Franklin County website.
What are the residential setbacks in Franklin County (2026)?
Setbacks in Franklin County come from the zoning code of the municipality the lot sits in: the front, side and rear distances depend on the lot's district. ParcelSheet does not draw setback lines or give a number it did not read; the county, township or city zoning office gives them for the district. See the Franklin County website.
Next to Franklin County: Delaware County, Fairfield County, Licking County, Madison County, Pickaway County, Union County.
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