ADU Pass
Champaign County
ADU Pass helps homeowners in Champaign County, Ohio navigate the permit paperwork for building an accessory dwelling unit. We cover 11 cities and 13 ZIP codes in this county.
Map
County ADU details
County ADU ordinance
Champaign County, Ohio (west-central Ohio between Springfield and Bellefontaine; ~38,800 residents; county seat Urbana; 12 townships - Adams, Concord, Goshen, Harrison, Jackson, Johnson, Mad River, Rush, Salem, Union, Urbana, Wayne; one city (Urbana) and ten villages or census-designated places (Cable, Casstown, Christiansburg, Conover, Mechanicsburg, Mingo, North Lewisburg, Rosewood, Saint Paris, Woodstock)) does NOT operate a countywide zoning resolution under O.R.C. Chapter 303. Ohio is a home-rule state under Article XVIII of the Ohio Constitution; counties may adopt county-tier rural zoning under O.R.C. Chapter 303 but only a small minority do (Lake County is the canonical example), and Champaign County has never adopted one. Land-use zoning in unincorporated Champaign County is delegated under O.R.C. Chapter 519 to each of the twelve townships, all of which DO maintain their own township zoning resolutions and zoning inspectors (Adams - Jon Marquis; Concord, Goshen - Wayne Russell; Harrison; Jackson; Johnson; Mad River - Greg McGlaun; Rush; Salem; Union; Urbana Township; Wayne - Randy Moore - per the county's published zoning-inspector roster). Inside the city of Urbana and the ten villages, municipal zoning controls. Champaign County does, however, operate a certified Champaign County Building Regulations Department (1512 S. U.S. Hwy. 68, Bay 13, Urbana - 937-484-1602) that enforces the Ohio Residential Code (OAC 4101:8) for one-, two-, and three-family dwellings across the unincorporated county and on a contractual basis for several of the villages - this distinguishes Champaign from Adams County and most other rural Ohio counties, where the Ohio Department of Commerce Division of Industrial Compliance is the residential plan reviewer of last resort. Subdivision review in the unincorporated county is handled by the Logan-Union-Champaign Regional Planning Commission (LUC RPC, headquartered in East Liberty) under the county's adopted subdivision regulations. ADU permissibility on a given parcel in unincorporated Champaign County is therefore set by the township zoning resolution applicable to that parcel; township resolutions in Champaign County generally do not include 'accessory dwelling unit' as a permitted accessory use and typically treat a second dwelling as requiring a Board of Zoning Appeals variance or conditional use - although the specifics vary township by township.
County assessor
Assessment policy: The Champaign County Auditor (Karen T. Bailey, as of 2026) 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 revaluation cycle (Ohio counties operate a six-year reappraisal cycle with a triennial update; Champaign County's cycle aligns with the Ohio Department of Taxation schedule) 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. Champaign County also administers Current Agricultural Use Valuation (CAUV) under O.R.C. § 5713.30 - § 5713.38; the county has substantial CAUV-enrolled acreage (the county's economy includes significant row-crop agriculture in the Mad River and Darby Plains regions). An ADU on a CAUV parcel may trigger recoupment (a three-year rollback) if the dwelling reduces qualifying agricultural acreage below program thresholds; CAUV reviewers in Champaign County 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. Board of Revision complaints (property-tax assessment appeals) for Champaign County parcels are filed with the County Auditor between January 1 and March 31 each year.
County overlays (5)
Known county issues (5)
- other — Researchers must contact the specific township zoning inspector before assuming ADU permission. Calendar time for a BZA variance pathway in a Champaign County township is commonly 60-120 days plus a $100-$400 BZA filing fee.
- other — ADU applicants in Champaign County deal with the county for residential plan review rather than waiting on state DIC travel routing. Permit lead times are correspondingly shorter than in counties without a certified building department; the county's fee schedule applies in place of the state schedule.
- other — Enumeration of Champaign County cities here includes these cross-county and split entries for fidelity to the city-highlights tree, but consumers should not attribute their full populations to Champaign County. The county's wholly-resident incorporated population is dominated by Urbana (~11,547), Saint Paris (~2,089), and Mechanicsburg (~1,599) plus smaller villages and unincorporated communities.
- other — ADU projects in these specific townships should expect additional review steps (Health District aquifer review near Cedar Bog; riparian-setback and possibly U.S. Army Corps Section 404 consultation near Big Darby tributaries) that can add 30-90 days and $1,000-$10,000 of consultant cost relative to a comparable unincorporated Champaign County parcel outside these zones.
- policy-review — Researchers should monitor the Ohio General Assembly for any future ADU preemption proposal. Until one passes, Champaign County ADU permissibility is a parcel-by-parcel question driven by the township or municipal zoning resolution and (for unincorporated parcels in Mad River Township or near Big Darby tributaries) the relevant environmental-overlay review.
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.