Do I need a permit for accessory dwelling unit (adu) in Unincorporated Johnson County?
We have not yet confirmed which office issues building permits in Unincorporated Johnson County. Ask the Johnson County Judge/Executive's Office who handles permits for your address before you start.
The requirements below come from Kentucky rules. They are not a statement that Unincorporated Johnson County issues or does not issue permits.
Yes. In Kentucky, accessory dwelling unit (adu) generally requires a permit, and Unincorporated Johnson County is no exception.
Kentucky has no statute requiring cities or counties to allow ADUs; a 2026 bill to make one ADU a permitted use in all residential zones (House Bill 203) was not enacted, so local zoning decides whether an ADU is allowed. The single-family exception covers only a single unit not connected to any other unit or building (815 KAR 7:125, Sections 1 and 2(2)(a)); an ADU attached to or inside the house creates a two-family dwelling, which that exception does not cover. Where a city or county has no local building inspection program, all construction projects except single-family dwellings must be submitted to the Department's Division of Building Codes Enforcement for review before work starts. Even where there is no local single-family program, the state HVAC division and the local electrical inspector still inspect the mechanical and electrical systems, and the Kentucky Residential Code still applies.
Get your exact answer
Answer a few questions to see the specific permits, documents, and next steps for your accessory dwelling unit (adu) in Unincorporated Johnson County.
Check my projectDocuments you may need
- Building permit application to the local building office, or plan review by the Department of Housing, Buildings and Construction for a two-family dwelling where no local program existsLikely required
- Site survey sealed by a Kentucky registered land surveyor for a new building or addition (KRC R105.3), unless the building official accepts other proofSometimes required
- Construction drawings and floor plan (KRC R106.1)Likely required
- Electrical permit for the new wiring (KRS 227.480)Required
- State plumbing permit (815 KAR 20:050) and state HVAC permit for the initial heating or cooling system (815 KAR 8:070)Likely required
Possible inspections
- Footing, foundation, and framing inspections by the local program, or by the Department where it has jurisdiction
- Electrical rough-in and final inspections
- Plumbing rough-in and final inspections, and the HVAC inspection
- Final building inspection where a permit was issued
Frequently asked questions
- Do I need a permit for accessory dwelling unit (adu) in Unincorporated Johnson County?
- Yes. In Kentucky, accessory dwelling unit (adu) generally requires a permit, and Unincorporated Johnson County is no exception. The documents and inspections sections on this page list what the building department typically asks for.
- Who issues the permit in Unincorporated Johnson County?
- We have not yet confirmed which office issues building permits in Unincorporated Johnson County, or whether one does. Ask the Johnson County Judge/Executive's Office, which is the county's main government office, who handles permits for your address. Your mailing city is not always the permitting authority.
- How do I find out the exact requirements for my project?
- Run the free PermitRoadmap check for your specific project and answers. It returns the likely permits, documents, inspections, and next steps, each linked to its official source.
PermitRoadmap is an independent informational service and is not affiliated with any city, county, state agency, or permitting authority. Results are informational and do not replace confirming requirements with the local permitting authority.