Accessory Dwelling Units
What is an Accessory Dwelling Unit (ADU)?
An Accessory Dwelling Unit (ADU) is an attached or detached residential unit that provides complete independent living facilities, including a bedroom, kitchen, and bathroom. A Junior Accessory Dwelling Unit can be no larger than 500 square feet and is contained entirely within an existing or proposed single-family home or accessory structure. A junior ADU may include its own bathroom, or share with the existing home.
In the single-family residential zoning districts (A, R-1, or HR zoning districts), one ADU and one junior ADU are allowed on a lot that contains an existing or concurrently approved single-family home. In the multi-family residential zoning district (R-M zoning district), up to two detached ADUs may be allowed. In addition, for every four dwelling units in a multi-family dwelling, one ADU may be created within existing non-habitable space, including, but not limited to, storage rooms, boiler rooms, passageways, attics, basements, or garages.
ADUs may be rented, but cannot be sold separately from the main home. For ADU applications received after January 1, 2025, the owner of the lot must also live on the lot.
The construction of an ADU or junior ADU are processed without a public hearing, subject to approval of a building permit. However, ADUs that result in the following will require Design Review prior to building permit submittal:
- A new multi-story main structure or multi-story accessory structure
- The conversion of a single-story structure to a multi-story structure
- A new structure over 18 feet in height or an existing structure that would exceed 18 feet in height as a result of the proposed construction
Legalization of Existing ADUs
ADUs and junior ADUs that were established within a permitted structure between August 18, 1984 and February 19, 2003 may apply for legalization with reduced development standards.
Summary of ADU Development Standards
|Conversion of an Existing Accessory Structure
Floor Area and Site Coverage