City · California

ADU rules in Riverside

3 sources

These are the primary sources for accessory dwelling unit regulations in Riverside: the city's own zoning code, planning department pages, and permit guides. Start here before talking to anyone: the rules below are what your permit reviewer will apply.

Rules at a glance

Detached (backyard) ADU

Allowed

ADUs are permitted in all residential zones, including all multi-family and mixed-use zones that include an existing or proposed dwelling; an ADU may be detached from the proposed or existing primary dwelling. Riverside also allows movable ADUs (MADUs) as a distinct detached category. On single-family lots the detached allowance is one new-construction detached ADU or MADU in addition to one attached or converted ADU and one JADU.

RMC 19.442.020; RMC 19.442.030(B)(3), (E)(1)

Attached or internal ADU

Allowed

An ADU may be attached to or located within the proposed or existing primary dwelling; if attached, the ADU (or JADU) must have independent exterior access separate from the primary dwelling. A JADU must be within the walls of the primary dwelling, with cooking facilities and either separate or shared sanitation facilities.

RMC 19.442.030(B)(3), (B)(4), (B)(5)

Maximum size

Attached ADU: 50 percent of the existing or proposed primary dwelling floor area or 1,200 sq ft, whichever is less, but at least 850 sq ft (one bedroom or less) or 1,000 sq ft (more than one bedroom) must be allowed; detached ADU: 1,200 sq ft max; JADU: 500 sq ft max; movable ADU (MADU): 150 to 430 sq ft; minimum size for any ADU or JADU is an efficiency dwelling unit per California Building Code Section 1208.4

No minimum lot size is required to establish an ADU, MADU, or JADU, and ADU floor area is not counted toward lot coverage.

RMC 19.442.030(D); RMC 19.442.030(A)(7), (A)(8)

Owner occupancy

Not required

On a lot with a primary dwelling and an ADU or MADU, neither unit is required to be owner-occupied. A JADU is different: one JADU is allowed only if the primary dwelling or the JADU is owner-occupied, recorded through a deed restriction.

RMC 19.442.030(F)

Extra parking

None; no parking spaces are required for any ADU, MADU, or JADU, and no replacement parking is required for the primary dwelling when a garage, carport, or covered parking is converted to an ADU

Riverside's ordinance waives ADU parking citywide, going beyond the minimum state-law exemptions.

RMC 19.442.030(H)

Approval process

Permitted use

ADUs, MADUs, and JADUs are permitted by right in all residential, multi-family, and mixed-use zones with an existing or proposed dwelling; approval is a staff-level compliance review to the satisfaction of the Community and Economic Development Director or designee, with no hearing or discretionary permit in the chapter. The chapter does not restate review timelines; state law (Gov. Code 66317, read on leginfo.legislature.ca.gov) requires ministerial approval or denial within 60 days of a complete application, with a 15-business-day completeness determination.

RMC 19.442.020; RMC 19.442.030

Rental restrictions

When rented, an ADU, MADU, or JADU must be rented for terms longer than 30 days (no short-term rentals); an ADU may not be sold or conveyed separately from the primary residence, except a primary dwelling and ADU developed by an IRS-recognized 501(c)(3) housing nonprofit or faith-based organization working with the Housing Authority to serve low-income households; JADUs carry a recorded deed restriction prohibiting sale separate from the primary dwelling

The separate-sale exception for qualifying nonprofits mirrors current state law.

RMC 19.442.030(A)(5), (A)(9), (A)(10)

The fine print: 7 caveats that can change the picture

Riverside regulates movable ADUs (MADUs) as a distinct category with their own standards: 150 to 430 sq ft, required water/sewer/electric connections, screening and design rules, no separate street address, and no placement between the primary dwelling and the street; MADUs are not permitted in any Historic District, Neighborhood Conservation Area, on lots with designated Cultural Resources, or on multi-family lots (RMC 19.442.030(A)(4), (B)(2), (E)(2)(c), (I), (J))
Historic properties: ADUs and JADUs in a historic district must also comply with RMC Title 20 and state ADU law, and the city publishes separate Historic Property ADU Design Standards (RMC 19.442.030(A)(3))
Unit counts are lot-type dependent: single-family lots allow one attached or converted ADU, one detached new-construction ADU or MADU, and one JADU; multi-family lots allow conversion ADUs in existing non-livable space up to 25 percent of existing units (minimum one), plus up to 8 new detached ADUs on lots with existing multi-family dwellings (not to exceed the number of existing units) or 2 on lots with a proposed multi-family dwelling (RMC 19.442.030(E))
Height is form dependent: single-story detached ADUs and MADUs capped at 20 feet, two-story detached ADUs and second-floor ADUs on existing accessory buildings at 30 feet, attached ADUs follow the underlying zone, and in the RC zone detached ADUs are limited to one story and 20 feet (RMC 19.442.030(G))
Setbacks scale with height: 4-foot side and rear setbacks apply to new one-story ADUs and MADUs under 16 feet, but ADUs over 16 feet and any second-story ADU must meet the underlying zone's setbacks, and front and street-side setbacks always follow the underlying zone (RMC 19.442.030(C))
City impact fees are waived for ADUs under 750 sq ft and charged proportionately to the primary dwelling's square footage at 750 sq ft and over; utility connection fees or capacity charges apply only to new detached units or ADUs built with a new primary dwelling, proportionate to size or plumbing fixtures (RMC 19.442.030(J), (K))
The city's Dwell Riverside program offers pre-reviewed permit-ready single-story ADU plans (746, 800, and 1,020 sq ft options) that go through standard building permit review as a faster alternative to custom plans

Summarized from Riverside's ordinance text, read July 2026; every row links the code section it came from. Rules often vary by zone and lot, so treat this as orientation, not a permit determination, and confirm with the planning department before you commit to a design.

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ADU regulations

California statewide law also applies

California sets baseline ADU rights at the state level. Where local rules are stricter than state law allows, state law usually wins, so both are worth reading.

See California statewide rules

Spotted something outdated?

Zoning codes change. If a link is dead or Riverside has updated its ordinance, report it and we'll verify against the official source.

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