Accessory Dwelling Units (ADU)

What is an ADU?

An ADU or Accessory Dwelling Unit is a smaller, secondary residential unit located on the same lot as the main residence. ADUs may be called by many names, including granny flats, carriage houses, basement apartments, or mother-in-law suites. ADUs provide complete, independent living facilities (which at a minimum includes permanent provisions for living, sleeping, eating, cooking and sanitation which are accessed independently). Two types of ADUs are allowed; they can be attached to the main residence or detached as a separate unit. 


Types of ADUS

What are the Rules for ADUs?
Summary of ADU Regulations

One ADU per single-family lot

  • The standards listed below apply to the development of an ADU on a single-family lot in a single-family zoning district. Multi-family zoning districts are permitted to have 2-units as the base density and shall not be required to comply with these special standards. 


  • Attached - All yard and setback requirements of the principal structure shall be met and it shall be located either to the side or behind the principal structure
  • Detached - All yard and setback requirements for an accessory structure (e.g., freestanding garage) shall be met and it shall be located either to the side or behind the principal structure


  • Attached - An exterior staircase used to access a second story or higher ADU shall not be located on the front façade of the structure
  • Detached - The exterior pedestrian entrance to the ADU shall be located facing the principal structure or side yard

Maximum Height:

  • Attached - Height shall not exceed the height of the principal structure
  • Detached - Height shall not exceed the maximum height permitted for an accessory structure or the height of the principal structure

No short term rentals (e.g., Air B&B) without conditional use permit approved by the Board of Zoning Adjustment

Property Maintenance: Any property maintenance violations within the last 12 months must be resolved

Parking: Off-street parking shall meet the requirements of Chapter 9 of the LDC

Environmental Constraints: New construction shall not be allowed on areas that contain environmental constraints

Owner Occupancy: The owner of the property shall reside within either the principal or the accessory dwelling unit

These provisions do not override any deed restriction or homeowners’ association declarations restricting ADUs

To view the full text of the adopted standards for Accessory Dwelling Units please visit the Land Development Code and view Section 4.3.27 available here:*

Land Development Code

*Not all cities with zoning authority have adopted these standards. Please consult the correct version of the code for your city or call us at (502)574-6230 with any questions.

Process to apply for an ADU
ADU Process Image


Step by Step Process Guide       ADU application

Events Showcasing ADU's
  • Louisville & Lexington ADU Conference: On February 1 & 2, 2022, Louisville and Lexington collaborated with AARP and AARP-Kentucky to host a conference offering national expertise in areas critical to the success of ADUs as an emerging housing type, including sessions on design and construction, appraisal, lending, and real estate. To watch these sessions and learn more about the role of each industry, please check out the conference site by clicking the button below:

Lou/Lex ADU Conference

  • White House Event on Making it Easier to Build Accessory Dwelling Units (ADUs):  On February 1, 2022, the White House hosted a virtual event on making it easier to build ADUs. Featured speakers included Ambassador Susan Rice, White House Domestic Policy Advisor; Sandra Thompson, Acting Director, Federal Housing Finance Agency; Lopa Kolluri, Principal Deputy Assistant Secretary, Office of Housing and the Federal Housing Administration, Department of Housing and Urban Development; Mike Hernandez, Vice President Engagement & Impact, Fannie Mae; and other housing experts and leaders. Watch the video below:

    General Resources
    Ordinance and Staff Report
    Research and Data
    ADU Application Look-up

    AARP Community Challenge Grant
    Neighborhood View of Accessory Dwellings
    ADU_Neighborhood View

    In coordination with the Office of Council District 21, the content curated on this page was made possible through the receipt of an AARP Community Challenge Grant. The grant's stated purpose was to "create community awareness of Louisville’s goals outlined within Comprehensive Plan 2040 by addressing equity issues related to affordable housing through Accessory Dwelling Units (ADUs), supporting older adults and minority communities." The project focused on 5 primary needs:

    1. Marketing strategy to spread community awareness
    2. Recording community experiences
    3. Digital outreach, including videos
    4. Baseline survey of community understanding
    5. Recommendations to Planning and Design Services for a community education model to be utilized for future LDC Reform efforts

    MKSK was selected as the consultant to meet these project goals. A final report, video, and resources were completed on May 31, 2022. 

    Final Report - Memo



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