Building permits in Jefferson County, Kentucky
Find the right authority before you build. Jefferson County permitting follows Kentucky law — here is exactly who issues the permit and where to start.
Cities issue permits
Louisville/Jefferson County Metro Government — Building Inspections
Louisville and Jefferson County operate under a consolidated city–county (Metro) government. The Louisville Metro Building Inspections division is the single building-permit authority for the entire Jefferson County metro area.
Open the official permit portal →
Permits and inspections are managed through the Louisville Metro online permitting portal; fees are based on project valuation under the Kentucky Building Code.
Permit cheat-sheet (Kentucky rules)
| Project | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | Conditional | city | Valuation-based; set by the issuing city. | — | Generally allowed | Kentucky has no statewide ADU mandate; local zoning governs. Lexington publishes an ADU permit guide, so ADUs are allowed there by ordinance. Confirm with the local planning department. Exempt: Local limits vary. |
| 🪵 Deck / Porch | Conditional | city | Valuation-based; set by the issuing city. | Lexington simple decks can be approved same-day if filed before 4 p.m. | Generally allowed | Attached decks and any deck above 30 in require a permit; footings below the local frost line (about 24 in in Lexington). Exempt: Freestanding decks 30 in or less above grade are typically exempt under the KRC (2015 IRC). |
| 🧱 Fence / Wall | Conditional | city | Lexington fence permits typically $75-$125 flat; set by city. | Often same-day/over-the-counter. | Generally allowed | Pool-enclosure fences must meet barrier requirements. Verify height and sight-triangle rules locally. Exempt: Lexington: residential fences over 4 ft in side/rear yards and all front-yard fences require permits. |
| 🛖 Shed / Outbuilding | Conditional | city | Valuation-based; set by the issuing city. | Small sheds often same-day/over-the-counter. | Generally allowed | Even when exempt, the shed must meet zoning setbacks and HOA rules. Exempt: Detached accessory structures 120 sq ft or less are typically exempt under the KRC. |
| 🪜 Basement Finish | Permit required | city | Valuation-based; includes trade permits. | Standard plan review 2-4 weeks. | Generally allowed | Finishing a basement that adds a bedroom requires an egress window. Exempt: Cosmetic finishing (paint, flooring) is exempt. |
| 🚗 Garage / Carport | Permit required | city | Valuation-based; includes trade permits. | New-structure plan review; varies by city. | Generally allowed | Attached and detached garages require a full building permit and plan review. Exempt: Detached garages over the 120 sq ft accessory-structure limit need a permit. |
| ☀️ Rooftop Solar PV | Permit required | city | Building + electrical permits; fee set by city. | Often over-the-counter for small residential PV. | Generally allowed | Provide racking structural design; follow utility interconnection rules. Exempt: No size exemption; rooftop PV always permitted. |
| 🌡️ HVAC Replacement | Conditional | city | Mechanical permit; fee set by city. | Trade permits often issued same-day. | Generally allowed | Equipment must meet current energy-efficiency rules. Exempt: In-kind replacement in the same location may be exempt per city. |
| 🍳 Kitchen Remodel | Conditional | city | Valuation-based when plumbing/electrical/structural work is included. | Standard review for permitted scopes. | Generally allowed | The KRC is a "mini/maxi" code — local governments may not adopt a different residential code. Exempt: Cabinet/countertop swap in the same layout is exempt. |
| 🛁 Bathroom Remodel | Conditional | city | Valuation-based when plumbing is relocated. | Standard review for permitted scopes. | Generally allowed | Ventilation to the exterior is required. Exempt: Fixture-for-fixture swap in place is often exempt. |
| 🏗️ Room Addition | Permit required | city | Valuation-based; includes trade permits. | Plan review varies by city (Lexington 3-4 weeks plus inspections). | Generally allowed | Lot-coverage and energy-code compliance are reviewed. Exempt: No exemption — any new conditioned footprint requires a permit. |
| 🪟 Window / Door Replacement | Conditional | city | Usually no fee for in-kind swap; permit needed if opening is enlarged. | In-kind swaps typically need no review. | Generally allowed | Replacement products should meet energy-code U-factor when the code is triggered. Exempt: Same-size, in-kind replacement is generally exempt. |
| 🏘️ Roof Replacement | Conditional | city | Often over-the-counter or exempt for same-footprint re-roof. | Same-day/next-business-day in many cities. | Generally allowed | Wind/snow-load design applies for new roofs. Exempt: Same-material, same-slope re-roof often exempt/over-the-counter. |
| 🅿️ Driveway / Parking Pad | Conditional | city | Building permit often not required; curb-cut/right-of-way work is separate. | Right-of-way permits reviewed by the city/utility. | Generally allowed | A separate right-of-way permit is usually needed to cut the curb or connect to the street. Exempt: Replacing a driveway in the same footprint (no new curb cut) is generally exempt. |
| 🏊 Swimming Pool / Spa | Permit required | city | Valuation-based; includes barrier/fencing and electrical bonding review. | Plan review 4-6 weeks; barrier inspection before filling. | Generally allowed | Pool barriers (self-latching gates, non-climbable fencing) are required locally. Exempt: Small portable/soft-sided pools may be exempt; permanent pools always permitted. |
| 🧱 Retaining Wall | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Taller or surcharge-supporting walls require a sealed design. Exempt: Walls 4 ft or less above grade and not supporting a surcharge are typically exempt under the KRC. |
| 💥 Demolition / Teardown | Permit required | city | Demolition permit fee set by the issuing authority; verify locally. | — | Generally allowed | A full teardown or major strip-out requires a demolition (building) permit. Demolition permits commonly require proof of utility disconnects (water, gas, electric, sewer) and may require asbestos/lead-paint clearance for pre-1978 homes before work begins. Verify the issuing authority for your specific property. |
| 🚰 Septic System | Permit required | county | Septic permit fee set by the local environmental/health authority; engineered systems cost more. | — | Generally allowed | New or replacement onsite wastewater (septic) systems require a permit from the state environmental/health department (or local health district). A soil/perc evaluation and engineered design are typically required; licensed installers perform the work and the system is inspected before backfill. |
| 🔌 EV Charger | Conditional | city | Electrical permit; fee set by the issuing authority. | — | Generally allowed | A home EV charging station (240V branch circuit + wall-mounted EVSE) requires an electrical permit and must meet the NEC (Article 625). Many jurisdictions fast-track residential EVSE. A load calculation and possible service upgrade are reviewed. |
| ⚡ Standby Generator | Conditional | city | Mechanical/electrical permit; fee set by the issuing authority. | — | Generally allowed | A permanently installed standby generator requires mechanical and electrical permits (transfer switch, fuel gas/propane line). Setback, carbon-monoxide ventilation, and noise rules apply; some HOAs restrict generator placement. |
Frequently asked questions
Who issues building permits in Jefferson County, Kentucky?
Louisville/Jefferson County Metro Government — Building Inspections is the permitting authority for Jefferson County. Permits are issued by the incorporated cities; the county handles only unincorporated areas. Start at the official portal linked above.
Do I go to the county or my city for a building permit in Jefferson County?
Permits are issued by the incorporated cities; the county handles only unincorporated areas.
What home projects need a permit in Jefferson County?
The same project types shown in the cheat-sheet above (ADU, deck, fence, shed, solar, and more) — rules follow Kentucky state law. Whether the county or your city issues it depends on your property's incorporation status.
How do I apply for a permit in Jefferson County?
Use the official permit portal linked above. Most offices accept online submissions; have your plans, site information, and contractor details ready before applying.