Hardin County

Unlike most Ohio counties where building permits are issued at the township level, Hardin County concentrates residential building-permit and electrical-permit intake at the county level through Hardin County Regional Planning, located in the courthouse in Kenton. An unincorporated-Hardin ADU project still has to clear multiple desks: (1) Township Trustees / township zoning officer -- zoning permit, BZA action where needed; (2) Hardin County Regional Planning -- building permit, electrical permit, residential plan review if 2,000+ sq ft under roof (including attached garages and covered decks); (3) Hardin County Health Department -- on-site sewage (HSTS) site evaluation, install permit, and well permit, required before the building permit can be issued for any dwelling or structure with plumbing; (4) Hardin County Engineer -- driveway/culvert (encroachment) permit on county roads, plus floodplain development permit for parcels in mapped SFHA; (5) Hardin County GIS / Tax Map office -- 911 address assignment at lot split. Permit applications are submitted in person at Regional Planning's Suite 130 office; email submissions are not accepted. Electrical contractors registered with the office may use an online portal for electrical permits only.

Process overview: Typical ADU intake sequence in unincorporated Hardin: (1) Confirm with the relevant Township zoning officer whether zoning has been adopted in that township, and if so whether a second dwelling is a permitted accessory use (in practice, almost always 'no' -- a BZA use variance is required); (2) Obtain HSTS site evaluation from the Hardin County Health Department prior to any building-permit issuance for a dwelling or structure with plumbing; (3) Submit building-permit application (and electrical-permit application) IN PERSON at Regional Planning, Suite 130 of the courthouse; if the host residence plus the proposed ADU together exceed the 2,000-sq-ft-under-roof threshold (which they almost always will) provide a full set of construction plans for review; (4) Pull driveway/culvert and floodplain development permits from the County Engineer; (5) Assigned 911 address from GIS / Tax Map office if a new structure is being addressed separately; (6) Call OUPS (1-800-362-2764) before excavation. Permits in Hardin are paper-based at intake; electrical permit submission has an online portal restricted to registered electricians.

Impact fees: Hardin County does not levy a residential impact fee. Building-permit and electrical-permit fees are set by Regional Planning per a published fee schedule (available in person at Suite 130 of the courthouse). Health Department charges per-permit fees for HSTS site review, install permit, inspections, and well permits. County Engineer charges per-permit fees for driveway/culvert and floodplain development permits. Townships that issue zoning permits charge a per-township zoning fee (typically modest, low hundreds of dollars).

In Ohio the County Auditor -- not a separately titled assessor -- is the chief assessing officer. Hardin County Auditor Michael T. Bacon maintains parcel-level real-estate records and conducts the statutorily required sexennial reappraisal and triennial update of real-property values under O.R.C. Title 57. Parcel-level data is available through the Hardin County Auditor's Beacon/Schneider portal (beacon.schneidercorp.com) and through the county's legacy real-estate search at realestate.co.hardin.oh.us. New construction -- including an ADU -- is captured on the tax roll the year following completion through field review (the Auditor's appraisers physically inspect new improvements flagged by Regional Planning building permits and by aerial-imagery change detection coordinated with Hardin County GIS). The Auditor's office administers the Ohio homestead exemption (O.R.C. 323.151-159) and the 2.5 percent owner-occupied tax reduction (the '2 1/2% Rollback'); both attach to the parcel's principal dwelling and do not extend to a separately metered or rented ADU.

Assessment policy: Ohio assesses real property at 35 percent of true (market) value (O.R.C. 5715.01). Hardin County's sexennial reappraisal and triennial-update calendar follows the Ohio Department of Taxation rolling schedule; consult the Auditor for the current cycle year. An ADU's improvement value is added to the host parcel's assessed value at the next regular update following completion; the host structure retains its prior valuation cycle. The 2.5 percent owner-occupied reduction and homestead exemption attach to the parcel's principal dwelling; a rented ADU does not gain a second homestead. Effective millage varies by taxing district (township + school district + JVS + library + park); the Auditor's per-parcel tax-bill computation in Beacon is the authoritative figure.

Hardin County administers three overlay-style layers that affect ADU feasibility: (1) a countywide floodplain regulation -- the county is the NFIP floodplain administrator for unincorporated territory, and a new FEMA FIRM/FIS update for Hardin County went through public-comment open house in November 2022 and into the formal adoption pipeline shortly thereafter; the Scioto River rises in Hardin (just north of Roundhead Township) and the Scioto plus its tributaries are the principal mapped SFHAs in the county; (2) state-managed water-resource exposure on the southwest corner of the county -- Indian Lake's northern shore reaches into Stokes Township in Logan County and the Indian Lake watershed (including Logan-Hardin border townships) carries elevated Health Department scrutiny following the March 14, 2024 EF-3 tornado that struck Russells Point and the lake's resort communities; (3) National Register historic resources -- Hardin County has seven National Register listings (per the NPS list complete through 2025-03-28), the most prominent of which is the 1915 Hardin County Courthouse in Kenton (NRHP 1979-03-21); historic-district design review is administered municipally where it exists (chiefly in Kenton's downtown), not at the county level. Hardin is not in a wildfire-WUI regime and has no coastal exposure.

• Hardin County Floodplain Regulations and FEMA NFIP Special Flood Hazard Areas (post-2022 FIRM revision) — Parcels that were Zone X under the prior FIRM may now be within SFHA following the post-2022 revision; pull the current FIRM at intake.
• Indian Lake watershed (Logan County state park, shared border with southwest Hardin) — Practically, Hardin parcels are governed by the county floodplain regulation and the township zoning book; the Indian Lake reference is included so that consumers in the southwest townships understand the watershed context.
• National Register historic resources (county-level inventory; design review administered municipally)
• Hardin County Subdivision Regulations (administered by Regional Planning) — Subdivision regs are not zoning -- they apply even in townships that have not adopted zoning. Lot-split surveys must be by a Registered Professional Surveyor.