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Accessory Dwelling Units (ADUs) / Secondary Units

Accessory Dwelling Units (ADUs) — also known as Secondary Units — are attached or detached accessory dwellings that provide independent living for one or more people, including permanent facilities for living, sleeping, eating, cooking, and sanitation. As of January 1, 2020, state and local laws surrounding ADUs have changed to allow for their construction with Single- and Multi-Family dwellings. See the "Documents" section below for new applications that conform to the latest requirements.

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To help expand housing options for Oakland residents, the City is streamlining the process for property owners to build Accessory Dwelling Units (ADUs) on their lots. As of January 1, 2020, state and local laws surrounding ADUs have changed.

Here are the new categories of ADUs under California state law:


  • JUNIOR ADU (JADU): Involves conversion of space within the building envelope of an existing or proposed Single-Family dwelling, resulting in a living unit of not more than 500 sq. ft., requiring owner occupancy in the JADU or primary dwelling unit.
  • CATEGORY ONE ADU: Involves either conversion of space within an existing Single-Family Dwelling, or conversion or rebuild of an existing accessory structure; includes no expansion of the existing building envelope other than up to 150 sq. ft. for purposes of accommodating ADU access and egress only.
  • CATEGORY TWO ADU: Involves construction of a new detached or attached structure, including an exterior addition to an existing structure to accommodate the ADU, in conjunction with a proposed or existing Single-Family dwelling.


  • CATEGORY ONE ADU: Conversion of a non-living space located within an existing Two-Family Dwelling or Multi-Family Dwelling Facility; maximum number of ADUs is up to 25% of existing units in building or one unit, whichever is greater.
  • CATEGORY TWO ADU: Construction of new detached structure(s); up to two ADUs per lot; 16 feet height limit; 4 feet side & rear setbacks.

    * Change of Occupancy regulations for the California Existing Building Code (CEBC) may apply when adding ADUs.

Please see the Documents section for new ADU applications that conform to the latest legal requirements.

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