Marin County, CA Accessory Structures: ADU Owner Occupancy (2026)

Section 22.32.125 lets a property owner voluntarily convert existing building area within a single-family home into a Junior Accessory Dwelling Unit (JADU) without the size and setback review a full ADU requires. To qualify, the JADU must be no more than 500 square feet, contained entirely within the single-family structure, include a kitchenette but not a full kitchen, and have its own separate entrance, with an interior connection to the main living area if it lacks its own bathroom. Only one JADU is allowed per property.

Owner occupancy is listed as a standalone eligibility criterion in Subsection E: 'The property shall be owner occupied, except that owner occupancy is not required if the owner is a government agency, land trust, or housing organization.' That means an investor who does not live on the property cannot create or maintain a JADU there under this section; the exemption is limited to institutional owners, not to individual landlords who rent out the primary residence.

Because the owner-occupancy condition runs with the property rather than the individual owner, Subsection F requires the property owner to record a deed restriction, running with the land, that prohibits selling the JADU separately from the single-family residence and restricts the unit to the size and attributes described in the section; a copy of the recorded deed restriction must be provided to the Agency. Selling the home to a new owner who does not occupy it does not by itself erase the deed-restricted JADU, but continued lawful operation of the JADU depends on the property remaining owner-occupied under the recorded terms.