ADU rules in Covington

Covington's Neighborhood Development Code (NDC, Chapter 158) lists the Accessory Dwelling Unit as a limited use (L, administrative approval against use-specific standards) in the RR, SR, SU, CRM, DTC and TUR districts. A detached ADU must sit in a Carriage House, which may stand alone or sit above a detached residential garage, and the Carriage House building type is permitted only in RR, SR, SU and TUR. Those four districts cover the city's ordinary single-family neighborhoods, from the suburban south (RR, SR) to the historic in-town blocks (SU, TUR). Where an improved alley adjoins the lot, vehicle access to the ADU must come from the alley.

The NDC calls attached units integrated ADUs: they may be carved out of a principal building (a basement unit, for example) or built as an addition, and are allowed as a limited use in RR, SR, SU, CRM, DTC and TUR. The exterior must not make the unit obvious: a separate door must look like ordinary secondary access (side or French doors), exterior stairs serving as the ADU's main entrance must be on the side or rear, and only one entrance may face the street unless more already existed. An addition built for the ADU must match the principal building.

The ADU's floor area (counting only the unit itself, not an attached garage or workshop) may not exceed 50 percent of the total square footage of the principal residential building or 1,000 square feet, whichever is less. For a detached unit, the Carriage House footprint is separately capped at 50 percent of the principal building's footprint or 1,000 square feet, whichever is less, and the Carriage House must be shorter than the principal structure on the lot. A site-built tiny house used as the ADU follows the Carriage House standards, and the NDC's tiny house rules cap any tiny house at 600 square feet of gross floor area.

Only detached ADUs carry an owner-occupancy rule, and only in some districts: in the RR, SR and mixed-use districts the owner must live in either the principal residence or the ADU. Among the districts that allow Carriage Houses, that covers RR, SR and TUR (a mixed-use district under Sec. 02.04.3), but not SU. Integrated ADUs have no owner-occupancy requirement in any district. The rule is written as a continuing use standard, not a one-time application test.

In the RR and SR districts one off-street space for the ADU is required on top of the principal dwelling's parking. Elsewhere the parking table's minimum for 'Accessory Dwelling Unit / Carriage House' is zero, and minimum ratios apply only in RR, SR, AUC, SO, SI and GI anyway; every district caps ADU parking at one space per unit.

An ADU is an 'L' (limited) use, which the NDC defines as subject to administrative review and approval against the Division 07 use-specific standards; no Board of Architectural Review and Development (BOARD) hearing is needed. The Administrator issues a Limited Use Authorization, which may be issued together with the building permit (Planning and Development Services of Kenton County handles both). Properties in Covington's local historic overlays also need a Certificate of Appropriateness for exterior work.

The NDC does not bar renting an ADU, but Chapter 155 requires a rental dwelling license for every rental unit, including units in otherwise owner-occupied buildings (three-year provisional license, then inspection; $30 for one unit per parcel, $60 for 2 to 4). For stays under 30 days, Chapter 127 requires a separate short-term rental license per unit ($500 initial, $250 renewal, with an inspection). A rental counts as host-occupied when the owner lives in the principal unit and the units share one PVA parcel number, which fits an ADU behind an owner-occupied house; host-occupied licenses are exempt from the historic district and neighborhood caps that limit non-host-occupied licenses (151 citywide, one per block face in most areas). Other limits: two licenses per structure, a 12-person occupancy cap, no events, none at all in City Heights, and the NDC lists host-occupied rentals as a limited use in most residential and mixed-use districts but a conditional use in RR. No provision on separate sale of an ADU was found.