ADU Rules in Louisville, KY (2026)
ADU rules, permit requirements, size limits, and fees for Louisville, KY. Source-cited from official municipal code.
Yes, ADUs are allowed in Louisville, KY.
Louisville, KY permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. State and local law governs the approval process. In Louisville, the Louisville Metro Planning and Design Services handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Louisville.
ADU Size Limits
ADU Size Limits in Louisville: Detached ADU: up to 900 sq ft (max height: 25 feet). Attached ADU: 45% of primary dwelling floor area. Louisville Metro LDC accessory dwelling unit provisions. Detached ADUs allowed up to 900 sqft in qualifying residential zones. JADU is a California-specific concept not applicable in Kentucky.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | 900 sq ft | 25 feet |
| Attached ADU | 45% of primary dwelling floor area | Per zone height limit |
Permit Fees
ADU Permit Fees in Louisville: Plan check fee: $150–$900. Building permit fee: Based on construction value — typically $700–$3,000. Impact fees: Louisville Metro charges MSD (Metropolitan Sewer District) connection fees; development fees are moderate. School fees: None or N/A. Total estimated permit cost: $2,000–$8,000 total fees. Louisville Metro MSD (Metropolitan Sewer District) connection fees apply for new wastewater connections. LG&E (Louisville Gas and Electric) connection fees for new electrical service. Louisville's fees are moderate compared to high-growth coastal cities.
| Fee Type | Amount |
|---|---|
| Plan Check | $150–$900 |
| Building Permit | Based on construction value — typically $700–$3,000 |
| Impact Fees | Louisville Metro charges MSD (Metropolitan Sewer District) connection fees; development fees are moderate |
| School Fees | None |
| Total Estimate | $2,000–$8,000 total fees |
Permit Timeline
Louisville ADU Permit Timeline: Louisville Metro Planning and Design Services permit: typically 4-8 weeks for residential permits. Online permitting through Louisville Metro government portal. Construction typically 4-14 months. Apply through the Louisville Metro Planning and Design Services online permit portal. Phone: (502) 574-3131.
Setback Requirements
ADU Setback Requirements in Louisville: Front setback: follows zone standard. Side setback: 5 feet. Rear setback: 5 feet. Louisville Metro LDC ADU setbacks. Minimum 5 ft rear and side setbacks for detached ADUs. Alley-access lots common in Louisville's older grid neighborhoods.
Parking Requirements
Parking Requirements: 1 parking space required per ADU. Louisville is auto-dependent — TARC (Transit Authority of River City) bus service is available but limited. No parking waivers for transit proximity in most residential zones.
Restrictions & Requirements
- ADU must be on same lot as primary single-family dwelling
- Lot must meet minimum size requirements for the residential zone
- ADU cannot be separately conveyed from primary parcel
- Total lot coverage must comply with LDC zone limits
- Louisville Metro STR registration required if ADU is used for short-term rentals
- Must comply with Kentucky Residential Building Code
How Many ADUs Are Allowed?
Number of ADUs Allowed in Louisville: Single-family lots: 1 ADU per single-family residential lot. Multifamily properties: Multiple units allowed by right in R-5 through R-8 zones. Louisville Metro allows one accessory dwelling unit per single-family lot. The 2003 city-county consolidation eliminated jurisdictional boundary issues for ADU development within Jefferson County.
Single-Family Lots
1 ADU per single-family residential lot
Multifamily Properties
Multiple units allowed by right in R-5 through R-8 zones
Historic District Considerations
Historic District Requirements: Louisville has 22 historic districts where additional design review may be required for ADU construction. Design review approval is required before obtaining a building permit for properties in historic overlay zones. Louisville has exceptional historic resources. Old Louisville (south of downtown) is the largest preserved Victorian neighborhood in the US — over 1,400 Victorian-era structures in approximately 45 blocks. Butchertown, St. James-Belgravia, and NuLu have locally designated historic districts. Louisville Landmarks Commission designates local landmarks and oversees design review for H overlay zones. Certificate of Appropriateness required for exterior changes to designated properties. Look up historic district boundaries at: https://louisvilleky.gov/government/develop-louisville/historic-preservation
Frequently Asked Questions
Can I build an ADU in Louisville?
Yes. Louisville, KY allows accessory dwelling units. On a single-family lot you can build 1 ADU per single-family residential lot.
How big can an ADU be in Louisville?
The maximum size for a detached ADU in Louisville is 900 square feet.
How long does it take to get an ADU permit in Louisville?
The typical ADU permit timeline in Louisville is Louisville Metro Planning and Design Services permit: typically 4-8 weeks for residential permits. Online permitting through Louisville Metro government portal. Construction typically 4-14 months.. Total estimated permit fees are $2,000–$8,000 total fees.
Do I need extra parking for an ADU in Louisville?
No, Louisville does not require additional parking for ADUs.
Do I have to live on-site to have an ADU in Louisville?
No, owner-occupancy is not required for ADUs in Louisville.
Source: Louisville Metro Land Development Code (LDC) — Accessory Dwelling Unit provisions. Last verified April 6, 2026. View source