ADU rules in Kenton County

The Official Zoning Ordinance of Unincorporated Kenton County has no accessory dwelling unit use in any zone, and Section 9.10 allows no more than one principal building and permitted accessory structure per lot except in the zones that say otherwise (R-2, R-3 and the commercial and industrial zones). The A-1, A-2, R-RE and R-1A to R-1G zones list only 'Customary accessory buildings and uses' as accessory uses, and a dwelling unit is defined as complete housekeeping facilities for a family, so a separate backyard cottage is not a customary accessory use. This ordinance covers only unincorporated land; Independence, Erlanger, Covington and the other Kenton County cities have their own ordinances.

No attached or internal ADU use exists. The closest route is a two-family dwelling, a permitted use only in the R-1BB, R-1DD and R-1EE zones (on larger lots than a single-family home: three-quarter acre in R-1BB, 13,500 sq ft in R-1DD, 11,500 sq ft in R-1EE) and in the R-2 and R-3 multi-family zones. Two-family dwellings are not allowed in the A-1, A-2, R-RE, R-1A, R-1B, R-1C, R-1D, R-1E, R-1F or R-1G zones that cover most rural unincorporated land. R-1BB also allows quarters for live-in domestic help inside the house, which is staff housing, not a rentable unit.

Because the county ordinance has no ADU use, it sets no ADU size limit. Where a two-family dwelling is allowed, the controls are the zone's lot area, lot width (80 ft for two-family in R-1DD and R-1EE, 100 ft in R-1BB), yards and height, not a unit size. The Z21 Blueprint template that several Kenton County cities have adopted caps ADUs at the lesser of 800 sq ft or 75 percent of the main house, but the county has not adopted it.

No ADU owner-occupancy rule exists because there is no ADU use, and the two-family dwelling route carries no owner-occupancy condition. The only owner-residence rules in the ordinance govern bed and breakfast establishments ('The owner shall live in the dwelling unit') and the owner-occupied short-term rental category in the A-1 and A-2 zones.

Section 11.2 requires two spaces for a one-family dwelling and four for a two-family dwelling, with individual access for each unit or a joint access on which no parking is allowed, so the second unit adds two spaces. A short-term rental in A-1 or A-2 needs one space per sleeping room or suite plus one for the caretaker.

Where the two-family route exists (R-1BB, R-1DD, R-1EE, R-2, R-3) it is a permitted use, so the path is a zoning permit from the PDS zoning administrator under Section 16.1 plus a building permit, with no Board of Adjustment hearing. There is no permit route at all for a second unit in the A-1, A-2, R-RE or other single-family zones short of a zone change.

The ordinance places no limit on long-term rental of either unit of a two-family dwelling. Short-term rentals appear only in the A-1 and A-2 agricultural zones: owner-occupied ones are a permitted use and non-owner-occupied ones a Board of Adjustment conditional use, both needing any required building permit, zoning permit and occupational license, a stay of 1 to 29 nights, and one parking space per sleeping room plus one. They may operate in the primary structure and/or one accessory structure, but not in mobile homes, RVs, sheds, garages, barns or other structures not typically used as a residence. No residential zone lists short-term rentals.