ADU Pass
Fayette County
ADU Pass helps homeowners in Fayette County, Ohio navigate the permit paperwork for building an accessory dwelling unit. We cover 4 cities and 5 ZIP codes in this county.
Map
County ADU details
County ADU ordinance
Fayette County, Ohio (south-central Ohio till-plains county; ~28,500 residents; county seat Washington Court House; ten townships — Concord, Green, Jasper, Jefferson, Madison, Marion, Paint, Perry, Union, and Wayne — and incorporated places Washington Court House (city), Bloomingburg (village), Jeffersonville (village), and Milledgeville (village)) does NOT operate a countywide zoning ordinance and has not adopted county-tier zoning under O.R.C. Chapter 303. Ohio is a home-rule state under Article XVIII of the Ohio Constitution; counties may adopt county zoning under O.R.C. Chapter 303 but a small minority do (Lake County is the canonical example), and Fayette County is not among them. The Fayette County Regional Planning Commission (FCRPC) handles subdivision plat review under O.R.C. § 711.10 for unincorporated parcels and shared subdivision standards for the participating municipalities, but does not regulate use or density. Townships in Fayette County may adopt township-tier zoning under O.R.C. Chapter 519; as of 2026-05, township zoning coverage in Fayette County is partial — Union Township (encompassing Washington Court House's immediate suburban fringe along US-35 and SR-41) and Jeffersonville-area Jefferson Township are the townships most likely to have a zoning resolution in force, while several outer agricultural townships (Wayne, Madison, Marion, Perry, Paint, Concord) operate without township zoning. Where neither county nor township zoning exists, an unincorporated parcel is effectively unzoned for land-use purposes; the Ohio Residential Code (OAC 4101:8) still governs construction standards for any dwelling, including an ADU, and the Fayette County Health District still governs septic permits, but there is no local zoning prohibition on a second dwelling on a parcel. ADU permissibility in unincorporated Fayette County therefore turns on (1) whether the parcel is in a township with zoning, (2) whether the parcel is inside the city of Washington Court House or one of the three village limits (in which case city/village zoning applies), and (3) whether the parcel can support a second septic field under OAC 3701-29 capacity rules. Fayette County participates in the I-71 / US-35 logistics corridor, which has produced unusual development pressure around Jeffersonville (Tanger Outlets, distribution centers), and around Washington Court House (US-35 corridor), but ADU policy itself remains entirely a township/municipal question.
County assessor
Assessment policy: The Fayette County Auditor is the elected property-assessment authority under O.R.C. § 5713.01. Ohio assesses real property at 35% of true value (O.R.C. § 5713.03). New ADU construction is added to the parcel record on the next regular reappraisal/update cycle (Ohio's six-year reappraisal / triennial update schedule under O.R.C. § 5713.01) and reassessed at true value as of January 1 following completion. The Ohio Owner Occupancy Credit (O.R.C. § 323.151 et seq.) provides a 2.5% reduction in tax on owner-occupied homestead. The Homestead Exemption (O.R.C. § 323.152) reduces taxable value by $25,000 for owners 65+ or totally and permanently disabled, subject to income tests. Fayette County also administers Current Agricultural Use Valuation (CAUV) under O.R.C. § 5713.30 - § 5713.38 — a particularly significant program here because Fayette County is one of Ohio's most heavily agricultural counties (corn, soybeans, hogs, cattle), with the large majority of unincorporated land enrolled in CAUV. An ADU built on a CAUV parcel may trigger a partial recoupment (rollback) if the dwelling reduces the parcel's qualifying agricultural acreage below the CAUV threshold, or removes the parcel's homesite area from agricultural use; CAUV reviewers in the Fayette County Auditor's office examine ADU additions case-by-case. Under O.R.C. § 5713.17, the owner must notify the Auditor of any construction or improvement valued over $2,000.
County overlays (4)
Known county issues (5)
- other — Researchers should verify the township for any specific parcel before assuming ADU prohibition or permission. Parcels in unzoned townships have unusually permissive ADU conditions for Ohio, constrained mainly by septic capacity and floodplain. Parcels in the zoned townships, inside Washington Court House, or inside the three village limits require township- or municipal-specific review.
- other — ADU applicants must coordinate across three or four separate state and county agencies rather than a single one-stop county counter. Lead times are correspondingly longer; DIC inspector trip routing from Reynoldsburg or a regional office adds friction relative to counties with their own staff. Within Washington Court House and the villages, the city/village handles its own plan review through its building department or shared services.
- other — ADU economics in unincorporated Fayette County are commonly dominated by the CAUV-recoupment question, not by permit fees or zoning. A 1-2 acre ADU homesite carved out of a CAUV-enrolled 80-acre farm can produce a meaningful one-time tax bill (the three-year recoupment) and a permanent shift of that acreage out of CAUV; the parent parcel typically remains enrolled at the reduced acreage. Researchers should treat the CAUV consult as a first-order cost item for unincorporated ADUs here.
- other — ADU projects in Jefferson Township and on the Washington Court House fringe along US-35 face the most active permitting environment in the county and should expect to engage township zoning, FCRPC subdivision review, and (where access is at issue) ODOT. ADU projects in the agricultural townships face a much lighter touch but more septic-and-soils review.
- policy-review — Researchers should monitor the Ohio General Assembly for any future ADU preemption proposal; until one passes, Fayette County remains in the rare position where unincorporated unzoned-township parcels are de facto permissive without any state preemption being needed. Conversely, ADUs inside Washington Court House depend entirely on the city's ordinance, with no state floor to fall back on.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.