Accessory Dwelling Units

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What is an accessory dwelling unit (ADU)?

A habitable dwelling unit detached from a single-family dwelling, on a permanent frost free foundation, connected to sanitary sewer and water services, that provides basic requirements for living, sleeping, eating, cooking, and sanitation and conforms to applicable building codes.


  • ADU’s are listed as accessory structures in our Land Development Code.
  • One ADU is allowed per lot, you can have up to 3 accessory structures on your lot.
  • Churches and all residential zoning districts are allowed to have ADUs.
  • ADUs are not subject to the 20% rental density restriction.
  • ADUs do not count towards the allowed amount of lot coverage.
  • ADUs can be located as part of a detached garage or can be their own separate structure.
  • Limit on size: cannot exceed 50% of the gross floor area of the main home or 1,000 square feet, whichever is less.
  • Constructed to be compatible with the main home and neighborhood.
  • Must be at least 10 feet from the main home.
  • Parking is not required, but have to provide unrestricted, improved access must be provided from the street to the ADU entrance.
  • Must have a kitchen, bathroom, sanitary and water services.
  • The ADU or main home may be rented if the owner of the property lives resides on the property.

Application Process

To apply for an Accessory Dwelling Unit, a building permit is required. A set of building plans and a Certificate of Survey would be required.

Learn more about building permits and inspections

Submit a building permit

If you want to rent out an ADU and the requirements are met, a rental license can be obtained. 

Learn more about rental licenses 


Accessory Dwelling Units: Model State Act and Local Ordinance - AARP (PDF)

Making Big Sense of Small Homes - AARP

Knowledgebase Collection: Accessory Dwelling Units - American Planning Association

Model Code for Accessory Dwelling Units - American Tiny House Association

As housing costs and economic segregation increase, Austin’s granny flats proliferate - The Architects Newspaper

The Granny Flats Are Coming - CITYLAB

How One Colorado City Instantly Created Affordable Housing - CITYLAB

Accessory Dwelling Units - City of Austin, TX

Seattle’s New Environmental Study on Accessory Dwellings Obliterates Obstructionists’ Claims - Sightline Institute

Washington Just Advanced the Nation’s Best ADU Reform. Here’s Why It’ll Help. - Sightline Institute

Jump Starting the Benefits of ADUs in Minneapolis - Streets MN

The 5 Immutable Laws of Affordable Housing - Strong Towns