ADU rules in Murrieta

Murrieta permits ADUs, detached units included, in all six single-family districts (RR, ER-1, ER-2, ER-3, SF-1, SF-2) and all four multifamily districts (MF-1 to MF-4) under Tables 16.08-1 and 16.08-2, with the Downtown Murrieta Specific Plan following state law. MMC 16.44.160.D allows one ADU plus one JADU on a single-family lot and two detached ADUs on a lot with an existing multifamily building, but both counts yield to Gov. Code 66323(a): a detached new-construction ADU can be combined with a conversion ADU and a JADU, and an existing multifamily lot may add up to eight detached ADUs (never more than its existing units). Review is ministerial through a building permit. From 1-1-2027, AB 956 (Ch. 791, Stats. 2026) raises the state-exempt count to two detached new-construction ADUs on a single-family lot.

Attached additions and conversions of space inside an existing or proposed home or accessory structure are permitted in the same districts. 16.44.160.F.1.c lets a conversion expand only as Gov. Code 66323 allows (150 sq ft, for ingress and egress), while additions follow the 50 percent rule in the city's IB-108. JADUs (up to 500 sq ft inside the walls of a single-family home, with a separate entrance and an efficiency kitchen) are permitted in the single-family districts; Table 16.08-2 does not list them in the multifamily districts, matching the single-family scope of Gov. Code 66333.

In practice Murrieta applies 1,200 sq ft for a detached ADU and 50 percent of the existing home's floor area for an attached one (IB-108, May 2024), the state default limits of Gov. Code 66314(d)(4)-(5); its 2026 permit activity reports show detached ADUs of 1,193 sq ft (BLDG-R-2025-04579, issued 1-28-2026) and 1,199 sq ft (BLDG-R-2023-02233, issued 5-12-2026). The codified text is thinner: since Ord. 610-24 (2024) swapped its legacy 65852.2 citations, 16.44.160.F.1.b ties attached and detached ADU size and setbacks to Gov. Code 66323, whose only cap is the 800 sq ft limit for the state-exempt detached unit, and a literal 800 sq ft maximum would fall below the 850/1,000 sq ft floor of 66321(b)(2), a conflict 16.44.160.I and 66325 resolve in favor of state law. A percentage cap can never block an 800 sq ft ADU with 4 ft side and rear setbacks (66321(b)(3)), every single-family lot can get the 800 sq ft state-exempt detached unit (16 ft height, 18 ft near major transit, plus 2 ft for a matching roof pitch), and JADUs are capped at 500 sq ft.

No for ADUs: 16.44.160.E.2 makes ADU occupancy rules consistent with Gov. Code 66315, which bars owner-occupancy conditions, and the city's IB-108 lists none. For a JADU the code still requires a recorded covenant that the owner live in the main home or the JADU, but since 1-1-2026 Gov. Code 66333(b) allows that requirement only when the JADU shares sanitation with the house, so a JADU with its own bathroom carries no owner-occupancy duty.

One off-street space per ADU beyond the main home's parking (16.44.160.G; Table 3-7 in 16.34.040 defers to it), waived within a half mile walking distance of public transit (Riverside Transit Agency fixed routes or council-designated service), in a historic district, where on-street permits are required but not offered, within one block of a car share, for ADUs inside the existing or proposed home or an accessory structure, and for JADUs. State law adds waivers the local list omits: an ADU applied for together with a new single-family or multifamily home (66322(a)(6)), the 800 sq ft state-exempt units of 66323 (66323(b) bars standards that section does not authorize), and studios, since 66314(d)(10)(A) caps parking at one space per unit or per bedroom, whichever is less. No replacement parking is required when a garage is converted or demolished for an ADU (66314(d)(11)).

Ministerial. 16.44.160.C and H require ministerial review without discretionary review or a hearing and a decision within 60 days of a complete application (deferrable only when filed with a new single-family home), IB-108 calls ADUs by-right with a building permit only, and Table 16.08-1 lists ADUs and JADUs as P (permitted with zoning clearance). The local text omits the 15-business-day completeness determination and the written appeal right of Gov. Code 66317(a)(2) and (d), which apply directly. On hillside lots, Ord. 638-26 (second reading 10-6-2026) keeps ADUs on developed parcels without retaining walls out of the hillside development permit but applies hillside design standards and tolls ADU approval for any required discretionary action such as grading.

ADUs and JADUs may be rented long term but not short term: 16.44.160.E.4 requires a recorded covenant against rentals under 30 days, 16.44.260.B.3 excludes ADUs and JADUs from the city's short-term vacation rental program (Ord. 561-20; an STVR is a rental of 30 consecutive days or less under 5.27.020, capped at 300 permits citywide), and IB-108 says an ADU may be rented only for a term longer than 30 days, matching Gov. Code 66323(e) and 66333(g) for state-exempt units and JADUs. An ADU may be sold separately only to a qualified buyer through a qualified nonprofit under Gov. Code 66340-66341 (16.44.160.E.3); Murrieta has adopted no Gov. Code 66342 ADU-condominium ordinance. No ADU rental registration or inspection program appears in the code chapters read.