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Accessory Dwelling Units (ADUs)

Learn More About Accessory Dwelling Units (ADUs)

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Image courtesy of the Casita Coalition

Accessory Dwelling Units (ADUs) are small, self-contained residential dwellings on the same lot as an existing or proposed single-family home or multi-family property. ADUs must have a kitchen, bathroom, place to sleep, and a separate entrance from the main property.

Types of Accessory Dwelling Units:

  • Detached ADU: The unit is separated from the primary structure.
  • Attached ADU: The unit is attached to the primary structure.
  • Conversion ADU: Space (e.g., master bedroom, attached garage, storage area, or similar use, or an accessory structure) on the lot of the primary residence that is converted into an independent living unit.
  • Junior Accessory Dwelling Unit (JADU): A specific type of conversion of existing space that is contained entirely within an existing or proposed single-family residence and shall contain no more than 500 square feet.

Below is the ADU Summary Table provides information on the zoning standards and regulations for ADUs and JADUs in Antioch, including setbacks, parking, maximum size, and height limits.

A Note on Unpermitted Units

If you have an unpermitted or informal ADU on your property (i.e., an ADU that was built without the required local permits), please call the Building Services Division at (925) 779-7065 to discuss options for retroactively receiving a permit.

Legalizing an unpermitted ADU can bring property owners peace of mind that they won’t be subject to code enforcement or tenant actions, as well as higher property values, assurance of insurance coverage, and increased safety.

adu table

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