Patriot

Gallia County has NOT adopted countywide zoning regulations as of 2026-05-20. Ohio law (O.R.C. Chapter 303) authorizes a Board of County Commissioners to put a countywide zoning resolution to voters in the unincorporated area, but the Gallia County Board of Commissioners has never done so. The county's regulatory presence in unincorporated territory is narrower than that of an urban Ohio county and is structured around the Gallia County Soil and Water Conservation District (Gallia SWCD), which administers BOTH (a) the Gallia County Subdivision Regulations under O.R.C. Chapter 711 through the county Planning Commission, and (b) the Gallia County Floodplain Regulations adopted in 1989 when the county joined the National Flood Insurance Program. Outside those two SWCD-administered domains, land-use authority sits at the township or municipal tier. The fifteen Gallia County townships (Addison, Cheshire, Clay, Gallipolis, Greenfield, Green, Guyan, Harrison, Huntington, Morgan, Ohio, Perry, Raccoon, Springfield, and Walnut) operate under O.R.C. Chapter 519, which would let any township adopt township zoning by trustee resolution with voter approval; as a matter of long-standing practice no Gallia County township is known to have adopted township zoning, leaving the entire unincorporated area of the county outside any zoning regime. The City of Gallipolis and the villages of Cheshire, Crown City, Rio Grande, and Vinton each administer their own municipal zoning under Ohio Constitution Article XVIII home rule. For accessory dwelling unit purposes, the practical consequence is that on an unincorporated Gallia County parcel there is no zoning step at all: a second dwelling proceeds through the Subdivision Regulations only if a lot split is involved, through the Floodplain Regulations only if the parcel sits inside a FEMA Special Flood Hazard Area, through the Gallia County Health Department's Environmental Health Division for septic and well review, and through the Ohio Residential Code (OAC 4101:8) administered by the responsible certified residential building department for the building permit itself. Inside a municipality, the city or village zoning code governs and the county Subdivision/Floodplain ordinances no longer reach.

• Gallia County Subdivision Regulations (administered by the Gallia County Planning Commission through the Gallia Soil and Water Conservation District under O.R.C. Chapter 711)
• Gallia County Floodplain Regulations (adopted 1989; current regulations_2021.pdf; administered by Gallia SWCD under 44 CFR 60.3 and the National Flood Insurance Program)
• O.R.C. Chapter 303 (county rural zoning) - the enabling statute Gallia County has NOT exercised
• O.R.C. Chapter 519 (township zoning) - the enabling statute under which Gallia County townships could but do not operate
• O.R.C. Chapter 711 (county and municipal subdivision platting authority)

State-floor overlay: Ohio has not enacted a statewide ADU preemption or by-right ADU statute. Ohio Constitution Article XVIII confers home rule on municipalities; O.R.C. Chapter 303 governs county zoning; O.R.C. Chapter 519 governs township zoning. No ADU-preemption bill has advanced past committee in the 134th, 135th, or 136th Ohio General Assembly. Gallia County's choice not to adopt countywide zoning, and its townships' choice not to adopt township zoning, are unconstrained by any state floor.

Gallia County's county-administered overlay jurisdiction is dominated by FEMA NFIP floodplain regulation in unincorporated areas, administered through Gallia SWCD under regulations originally adopted in 1989 and updated in 2021. The county does not maintain a separate county historic-district overlay; the Gallipolis Historic District is a city-administered overlay. Gallia County sits on the Ohio River for its entire southern boundary, which creates a substantial Special Flood Hazard Area footprint along the Ohio River bottoms (Addison, Gallipolis, Cheshire, Crown City, Hockingport-area) and along major tributaries including Raccoon Creek (which runs north-to-south through the western portion of the county) and Symmes Creek. The county is also adjacent to the Wayne National Forest's Athens Unit, which extends into northern Gallia County and creates a federal-land footprint that constrains private development in the northern townships. Current Agricultural Use Valuation (CAUV) under O.R.C. § 5713.30 applies on substantial agricultural acreage in Gallia County; placing an ADU on a CAUV-enrolled parcel may trigger recoupment of prior-three-year tax savings on the converted homesite portion.

• FEMA NFIP Special Flood Hazard Areas in unincorporated Gallia County — A new ADU in a mapped SFHA must be elevated with its lowest floor at or above the Base Flood Elevation. SWCD publishes Zone A, Zone AE, Floodway, and Substantial Improvement fact sheets through its floodplain page. The FEMA National Flood Hazard Layer should be consulted for the parcel-specific SFHA delineation before ADU project planning; the Ohio River frontage is unusually wide in Gallia County (the river is on average wider here than upstream) so SFHA delineations on river-adjacent parcels can extend substantially inland.
• Wayne National Forest - Athens Unit (northern Gallia County interface) — The federal-forest footprint is most relevant to ADU projects on parcels in the northernmost Gallia County townships. Parcels available for new ADU construction in those areas are concentrated in valley-floor and ridge-line private inholdings.
• Current Agricultural Use Valuation (CAUV) parcels — CAUV recoupment is a material project cost on any ADU built on previously enrolled agricultural land. The recoupment is calculated as the difference between CAUV-valued taxes and full-fair-market-value taxes for the prior three tax years on the converted portion. Owners contemplating an ADU on CAUV land should request a recoupment estimate from the Auditor before finalizing the project budget.
• Gallia County Sewer Districts (Bidwell/Porter, Green/Kanauga/Addison, Mercerville) — Sewer tap and connection fees on the three county sewer districts are published through the Gallia County Sewer/Sanitation office accessible from the Gallianet portal. Confirm sewer-service status for the specific parcel before pricing an ADU project; sewer tap can add several thousand dollars to total project cost on a parcel inside a service-area boundary.

Gallia County does not operate a combined building-and-zoning department for unincorporated territory because the county has no zoning to enforce. The county's permitting workflow for an ADU-style project on an unincorporated parcel routes across three independent offices: (1) the Gallia Soil and Water Conservation District (Gallia SWCD), 111 Jackson Pike, Suite 1569, Gallipolis, OH 45631, phone 740-446-6173, which administers the Subdivision Regulations through the county Planning Commission AND administers the Floodplain Development Permit Application for Special Flood Hazard Areas; (2) the Gallia County Health Department Environmental Health Division, phone 740-441-2943, which reviews on-site sewage treatment system (septic) installations and private water supply (well) installations under O.R.C. Chapter 3718 and OAC 3701-29; and (3) the responsible certified residential building department, which issues the building permit under the Ohio Residential Code (OAC 4101:8). Gallia County does not appear to operate an in-house county residential building department. Where no local certified residential building department (RCBD) has been chartered with jurisdiction over an unincorporated parcel, residential building-code enforcement defaults to the Ohio Department of Commerce Division of Industrial Compliance under O.R.C. § 3781.10. Applicants should phone the Gallia County Commissioners' office at the courthouse to confirm which certified building department currently serves a specific parcel before filing a building permit application. For an ADU-style project, the realistic sequence is: jurisdictional check at SWCD to confirm the parcel is unincorporated and whether it sits inside a Special Flood Hazard Area; Floodplain Development Permit if in an SFHA; Gallia County Health Department septic/well review (almost all unincorporated parcels in this Appalachian county rely on private septic and well); residential building permit through the responsible certified residential building department under OAC 4101:8; inspections (footing, foundation, framing, rough trades, insulation, final); certificate of occupancy and notification to the County Auditor for supplemental assessment.