ADU rules in Orange

Detached ADUs are an accessory use (A*) in every single-family (R1), two-family (R2), R-3 and R-4 zone under Table 17.13.030, which does not list them in the MH mobile home zone; the table also marks them A* in the OP, commercial, mixed-use and A1 zones, but 17.29.020(B) confines ADUs to lots zoned for single-family or multifamily dwellings with a primary residence, or lots developed solely with a legal nonconforming permanent residence. Locally a single-family lot may have one detached new-construction or converted-accessory-structure ADU where no attached ADU exists, and a lot with an existing multifamily building at most two detached ADUs (17.29.040(B)(4) and (B)(6)). State law overrides both counts: Gov. Code 66323(a) requires ministerial approval of a detached new-construction ADU of up to 800 sq ft with 4-ft side and rear setbacks in any combination with a converted ADU and a JADU, and of up to eight detached ADUs (never more than the existing unit count) beside an existing multifamily building. Review is ministerial with no hearing (17.29.030(E)).

An attached ADU may be created within the existing or proposed living area of a single-family home, in attached non-habitable space such as an attached garage, or as a new addition; locally one attached ADU is allowed per lot where no detached ADU exists, and an existing JADU may be converted to an attached ADU (17.29.040(B)(3)). Additions may bring the ADU up to 850 sq ft (one bedroom) or 1,000 sq ft (two or more) where zoning-district setbacks are met, or 800 sq ft with setbacks down to 4 ft, while pure conversions may grow only 150 sq ft for ingress and egress. A JADU of up to 500 sq ft may be created within a single-family home or its attached garage on a single-family-zoned lot with no footprint expansion (17.29.040(A), 17.29.050(A)). On multifamily lots the code allows ADUs converted from non-livable space (at least one, up to 25 percent of existing units). Gov. Code 66323(a)(1) lets a converted ADU combine with a JADU and a detached unit despite the local one-ADU rule.

17.29.050(B) caps new ADUs at 850 sq ft with fewer than two bedrooms and 1,000 sq ft with two or more; ADUs built within the living area of an existing home or the existing floor area of a detached accessory structure are instead limited to that space plus up to 150 sq ft for ingress and egress (17.29.050(B)(3)). 17.29.060(A) also limits an attached or detached ADU to 50 percent of the existing single-family home while always permitting 800 sq ft, and 17.14.160(E) caps all accessory structures on a lot at 50 percent of the principal structure with the same 800 sq ft allowance, so units between 800 and 1,000 sq ft need a large enough house. ADUs over 800 sq ft must meet the zoning district's side and rear setbacks (17.29.080(C)); smaller ones get 4-ft side and rear setbacks. Heights under 17.29.095 match Gov. Code 66321(b)(4): 16 ft detached, 18 ft within one-half mile of a major transit stop or high-quality transit corridor (plus 2 ft to match the home's roof pitch) or beside a multistory multifamily building, and 25 ft or the zone limit, whichever is lower, for attached units, at most two stories. The state-exempt detached unit under Gov. Code 66323(a)(2) is capped only at 800 sq ft of livable space, whatever the size of the house.

No owner occupancy for ADUs. 17.29.120(B) deferred an owner-occupancy rule for new ADUs until after January 1, 2025 only 'if the applicable provision of state law is not extended'; Gov. Code 66315 now bars any owner-occupant requirement on ADUs with no sunset, so the deferred rule never took effect (Ord. 20-24's recitals list AB 976 among the state changes). For JADUs, 17.29.120(C) and the city's February 2025 application packet still require the owner to live in the house or the JADU in every case, but since January 1, 2026 Gov. Code 66333(b), as amended by AB 1154, permits that requirement only where the JADU shares sanitation facilities with the main home, so a JADU with its own bathroom carries no owner-occupancy duty. The JADU deed restriction (17.29.200) still bars separate sale and fixes the unit's size and attributes.

17.29.130(B) requires one additional 10 by 20 ft space per ADU or per bedroom, whichever is less, and locally counts a tandem driveway space only outside the zoning-district setback. 17.29.130(D) waives parking within one-half mile walking distance of public transit, in an architecturally and historically significant historic district, for ADUs within the existing or proposed home or an accessory structure, where on-street permits are required but not offered, and within one block of a car-share space; Gov. Code 66322(a)(6) adds a waiver the local list omits, for an ADU applied for together with a new single-family or multifamily dwelling. HCD's March 2026 handbook adds that no parking may be imposed on Gov. Code 66323 state-exempt units and that a studio adds no bedroom, so on the city's own 'whichever is less' wording a studio needs no space, although the city FAQ says every ADU needs one. Garage or carport spaces lost to an ADU need not be replaced (Table 17.34.060; Gov. Code 66314(d)(11)); JADUs need no added parking, but 17.29.130(A) still requires replacing the house's required parking when a garage becomes a JADU, which sits uneasily with Gov. Code 66334(a).

An ADU or JADU first needs a Planning Division ADU Application, which 'shall be considered without discretionary review or a hearing and approved ministerially' if it meets Chapter 17.29, with action due within 60 days of a complete application; building permit plan check follows (17.29.030(E)-(G)). The application fee matches the Administrative Design Review fee, but no design review hearing or conditional use permit applies, and an Administrative Adjustment cannot reduce ADU setbacks (17.29.080(B)(3)). In historic districts and on inventoried historic properties the ADU must meet objective historic design standards (17.29.055), and the application packet requires a Historic Resource Assessment by a qualified preservation professional, still within ministerial review. Gov. Code 66317(a) also requires a completeness determination within 15 business days, shorter than the 30-day review per submittal the city checklist describes.

17.29.120(A) lets an ADU be rented separately from the house but not sold or otherwise conveyed separately, and 17.29.120(D) requires ADU and JADU rentals to run longer than 30 days and makes them ineligible as short-term rentals. Orange licenses short-term rentals (stays under 30 consecutive days) under Chapter 5.94 (Ord. 05-21, effective June 10, 2021) with a cap set by council resolution that the city page puts at 125 permits, reached, with applications closed and a waitlist; Chapter 5.94 reaches habitable accessory structures, but a permitted ADU or JADU cannot use it. For ordinary ADUs the 'longer than 30 days' rule runs one day past Gov. Code 66315, which lets a city require terms of '30 days or longer' (the city FAQ itself says 30 days or more), while Gov. Code 66323(e) and 66333(g) independently require terms longer than 30 days for state-exempt units and JADUs. The code has no exception for the qualified-nonprofit sale allowed by Gov. Code 66341 (HCD flagged its absence in 2022) and no Gov. Code 66342 condominium opt-in.