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

Since Ordinance No. 6544 (adopted December 9, 2025), the county's JADU rules live in Sonoma County Code § 26-24-150, and the old § 26-88-061 now reads "Reserved." Subsection C(1) sets the ownership rules. A JADU can be rented but cannot be sold separately from the single-family residence. The property owner must live in either the JADU or the remaining part of the house. Two exceptions lift that owner-occupancy duty: the JADU has sanitation facilities separate from the main dwelling, or the owner is a governmental agency, land trust, or housing organization. In practice, an owner who builds a JADU with its own bathroom can live elsewhere and rent out both units, while an owner who shares a bathroom with the main house must stay on site in one of the two spaces.

A JADU is a unit of no more than 500 square feet contained entirely within a single-family residence, and it may include its own sanitation facilities or share them with the main structure. Subsection C(2) bars rentals of 30 days or less, so short-term rental use is off the table. Subsection C(3) requires the owner to record a deed restriction that prohibits separate sale, states that the restriction runs with the land and binds future owners, limits the size and attributes of the JADU to those in Government Code Section 66333, and makes the County a third-party beneficiary with the right to enforce it.

The unit itself must meet the standards in subsection F: one JADU per lot, created from space inside an existing or proposed single-family dwelling (including enclosed uses such as an attached garage), a separate exterior entrance, an efficiency kitchen with a cooking facility and a food preparation counter with storage cabinets, and no additional parking. If the bathroom is shared with the main house, there must be interior entry to the main living area, and the shared bathroom is not counted in the 500 square foot floor area. JADUs are exempt from Design Review, and subsection G sends new JADUs through the same permit process as ADUs under § 26-24-020, where a complete ADU application with an existing primary dwelling must be approved or denied within sixty days. Subsection H lets unpermitted JADUs created before January 1, 2020 be legalized through the ADU process.

For detached or attached ADUs, § 26-24-020(C) imposes no owner-occupancy duty of its own: ADUs can be rented, cannot be conveyed separately from the primary residence except as State law provides, and cannot be rented for 30 days or less.