ADU rules in Riverside

Riverside permits ADUs, movable ADUs (MADUs) and JADUs in all residential zones and in multifamily and mixed-use zones with an existing or proposed dwelling, and an ADU may be detached from the primary dwelling. The citywide use table marks ADUs P (permitted) in the RC, RA-5, RR, RE, R-1, R-3, R-4, MU-N, MU-V and MU-U zones and X (not permitted) in the office, commercial, business-park, industrial and public-facility zones. On a single-family lot the code allows one new-construction detached ADU or MADU alongside one attached or converted ADU and one JADU; on a multifamily lot up to eight new detached ADUs (not more than the number of existing units) or two with a proposed multifamily building.

An ADU may be attached to, or located within, the proposed or existing primary dwelling, and an attached ADU or JADU must have its own exterior access. A JADU must sit within the walls of the primary dwelling and include cooking facilities (appliances, a food preparation counter, refrigeration and storage), with either its own or shared sanitation.

The code measures 'total floor area' (MADUs within the exterior faces of the exterior walls), while state law states its size floors in interior livable space. There is no minimum lot size for an ADU, MADU or JADU, and ADU floor area does not count toward lot coverage. A garage or other existing structure converted to an ADU needs no additional setback.

On a lot with a primary dwelling and an ADU or MADU, neither unit has to be owner-occupied. The code still says a JADU is allowed only if the primary dwelling or the JADU is owner-occupied, recorded in a deed restriction, but since January 1, 2026 state law (Gov. Code 66333(b), as amended by AB 1154) lets a city require owner occupancy only when the JADU shares sanitation facilities with the main home, so a JADU with its own bathroom carries no owner-occupancy requirement even though the city text has not been updated.

Riverside waives ADU parking citywide, beyond the state-law exemption zones, and the parking requirements table repeats the rule ('No parking is required for the ADU or JADU'). The waiver applies to every ADU type, including new detached units.

ADUs, MADUs and JADUs are permitted by right; an application must show compliance with the chapter's standards to the satisfaction of the Community and Economic Development Director or designee, with no hearing or discretionary permit, followed by a building permit. State law (Gov. Code 66317) requires a completeness determination within 15 business days and ministerial approval or denial within 60 days of a complete application. On designated historic properties the unit must also comply with Title 20 and the city's Historic Property ADU Design Standards, which can add a staff-level Certificate of Appropriateness.

Riverside's short-term rental chapter (Chapter 5.55, rentals of 30 consecutive days or less) excludes dwelling units with government-imposed restrictions against short-term rental, which covers ADUs under the 30-day rule. State law separately requires terms longer than 30 days for JADUs and state-exempt units (Gov. Code 66333(g), 66323(e)), while Gov. Code 66315 lets a city require only terms of 30 days or longer for other ADUs, so the city rule is one day stricter than the state allowance for those units. Separate sale by a qualified nonprofit is governed by Gov. Code 66341, and Riverside has not adopted the optional ADU condominium conversion under Gov. Code 66342.