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

090(A) of the Riverside County Code splits owner-occupancy requirements by accommodation type and permit date. For an accessory dwelling unit permitted between January 1, 2020 and June 1, 2025, the property owner is not required to occupy either the primary dwelling or the ADU. For an ADU permitted after June 1, 2025, the property owner must occupy, or live within, the primary dwelling or the ADU on the same lot. Acceptable proof of occupancy, as determined by the county, includes utility bills or official mail in the property owner's name, a government-issued ID or license showing the primary address, or documents showing the address is registered as the owner's residence.

The rule is stricter for second units and guest quarters: under subsections (A)(2) and (A)(3), the owner must occupy the primary dwelling itself for a second unit, while for a junior ADU the owner must occupy either the primary dwelling or the junior ADU. Owner-occupancy does not apply at all, per subsection (A)(4), when the property owner is another governmental agency, a land trust, a housing organization or a similar entity. Subsection (A)(6) layers on a related restriction: no additional residential accommodation, including an owner-occupied ADU, can be rented for a period of thirty days or less, closing off short-term rental use even where owner-occupancy itself is not required.

Subsection (A)(9) allows a home business or occupation inside the unit if otherwise permitted by state or local law, and subsection (A)(10) bars selling an ADU as a separate unit unless the lot is subdivided under state and local subdivision law.