ADU rules in Chino

Detached ADUs are a permitted (P) use in every residential district (RD1, RD2, RD4.5, RD8, RD12, RD14, RD20) and the AG district under the Comprehensive Zoning Code Update, Ord. No. 2026-008 (adopted 7-21-2026, effective about 8-20-2026), which moved the ADU rules from former § 20.11.020 into new Chapter 20.503. The adopted text still says a single-family lot may have no more than one ADU and one JADU (§ 20.503.020.A.2.a), but Gov. Code § 66323(a) requires ministerial approval of any combination of a conversion ADU, a JADU and one detached new-construction ADU of up to 800 sq ft with 4 ft side and rear setbacks, and the chapter's own building-permit-only list allows that detached unit 'in addition to any JADU' (§ 20.503.030.A.1.b); state law controls (§ 66325(a)). On multifamily lots the update now allows up to eight detached ADUs beside an existing building (never more than its existing units) and two beside a proposed one, plus conversions of up to 25 percent of the units, matching § 66323(a)(3)-(4). Detached units are limited to one story and 16 ft (18 ft near a major transit stop or high-quality transit corridor, plus 2 ft for roof pitch); footnote [4] still bars an ADU on top of a detached garage in RD1, RD2, RD4.5 and AG although § 20.503.020.A.1.a now allows ADUs 'in or above a detached garage'. From 1-1-2027 AB 956 (Ch. 791, Stats. 2026) allows two detached new-construction ADUs on a single-family lot under § 66323.

Attached and internal ADUs are allowed with any single-family or multifamily home, including conversions of existing living space, a garage or an accessory structure, with up to 150 sq ft added for ingress and egress (§ 20.503.020.A.1, B.1.b); attached and internal units need a separate entrance but no passageway (A.4). JADUs of up to 500 sq ft must sit within or attached to a single-family home on a lot zoned for single-family residences (A.1.c), and the use tables permit them in RD1 to RD8, RD12 and AG but not in RD14 or RD20. Ord. 2026-008 fixed the height conflict HCD flagged in 2023: attached ADUs may now be two stories and 25 ft, or the main home's height limit if lower, matching Gov. Code § 66321(b)(4)(D) (the repealed § 20.11.020 held every ADU to one story and 16 ft). A conversion ADU plus a JADU on a single-family lot, and conversions of non-livable space in existing multifamily buildings (at least one, up to 25 percent of the units), need only a building permit (§ 20.503.030.A.1.a, c).

Table 20.503-1 as adopted by Ord. 2026-008 caps detached ADUs at 1,600 sq ft in the RD1 and RD2 districts and 1,200 sq ft in every other zone, and attached ADUs at 50 percent of the existing home alongside the same 1,600/1,200 sq ft figures. The redline strikes both copies of 'whichever is less' from the attached cell, so the adopted wording no longer says how the two limits combine (the repealed § 20.11.020 said 'whichever is less'), and an attached unit on a small home is still guaranteed 800 sq ft by Gov. Code § 66321(b)(3), which the local 800 sq ft clause (§ 20.503.020.B.1.c) states only for lot coverage. The update deleted the rule capping detached ADUs at 80 percent of the main home's floor area, raised RD1 and RD2 lot coverage to 30 percent for ADUs, and dropped the JADU cap to a flat 500 sq ft; the state-exempt detached unit is 800 sq ft (§ 20.503.030.A.1.b). Footnote [1] still measures the caps over the whole structure including an attached garage or storage, where state law counts interior livable space (§§ 66321(b)(2)-(3), 66313(d)). Heights: detached one story and 16 ft, or 18 ft within one-half mile walking distance of a major transit stop or high-quality transit corridor plus 2 ft for roof pitch; attached two stories and 25 ft or the home's limit if lower; 18 ft on a multifamily lot. If Ord. 2026-008 never reached HCD within 60 days, § 66326(d) would void it and the state standards (1,200 sq ft detached under § 66314(d)(5)) would replace the 1,600 sq ft RD1/RD2 figure.

Nothing in Chapter 20.503 requires the owner of a property with an ADU to live there, consistent with Gov. Code § 66315, which bars owner-occupancy conditions on ADUs. For JADUs, § 20.503.020.B.6 (carried over unchanged from former § 20.11.020.B.10) still says the property owner 'must reside in any single-family residence that includes a junior accessory dwelling unit', but since 1-1-2026 Gov. Code § 66333(b) (AB 1154) allows that requirement only where the JADU shares sanitation facilities with the house, so a JADU with its own bathroom carries no owner-occupancy requirement and state law controls (§ 66325(a)); HCD's 2-27-2026 letter to the city lists this 2025 change. JADU approval still requires a recorded deed restriction against separate sale (B.7), which the owner can have removed by eliminating the JADU.

As amended by Ord. 2026-008, § 20.503.020.B.3.a requires one on-site space 'for each accessory dwelling unit bedroom', while the new parking table (Table 20.511-1) still says one covered or uncovered space per ADU; Gov. Code § 66314(d)(10)(A) caps ADU parking at one space per unit or per bedroom, whichever is less, so a new local-standards ADU needs at most one space and a studio none. No space is required within one-half mile walking distance of public transit, in an architecturally and historically significant historic district, for a unit entirely within the home or an accessory structure, where on-street permits are required but not offered, within one block of a car-share vehicle, or when the ADU is filed together with a new home (§ 20.503.020.B.3.d, which now includes the § 66322(a)(6) case), and none is required for a JADU (B.3.b). Required parking may be tandem on a driveway or in setbacks (B.3.c, e), and garage, carport or covered spaces lost to an ADU need not be replaced (B.3.f); § 66314(d)(11) extends that to uncovered spaces, and § 66323(b) bars parking standards on state-exempt units.

§ 20.503.030.A.1 lets the state-exempt categories (a conversion ADU plus a JADU, one detached unit of up to 800 sq ft with 4 ft setbacks, multifamily conversions and detached multifamily units) proceed on a building permit alone, and every other ADU needs a building permit plus the Director's ministerial approval under § 20.603.090(D) (A.2); the use tables list ADUs and JADUs as P, permitted by right without discretionary review. The city must approve or deny within 60 days of a complete application, or 30 days for a city pre-approved plan, or the application is deemed approved (A.3, B.6), and a denial must list every deficiency (A.4), consistent with Gov. Code § 66317. The only discretionary path is optional: an ADU that does not meet an objective standard may seek a minor (Director) or major (Planning Commission) variance (§ 20.503.030.F). The city ADU page offers four pre-approved detached plans (studio, one, two and three bedrooms).

§ 20.503.020.B.2.b (Ord. 2026-008) lets an ADU or JADU be rented separately from the main home if the owner holds a city business license (unless the City Manager grants an exemption under § 5.04.070), but never 'for a term of less than 31 consecutive days'. CMC § 8.95.030 (Ord. 2022-014, 11-1-2022) separately makes it unlawful to host, rent or advertise any residential dwelling or portion of one for 30 consecutive days or less anywhere in the city, the residential use tables list short-term rentals as not permitted, and renting two or more rooms of an ADU under separate leases makes it a boardinghouse, which the single-family districts prohibit. The 31-day floor is one day stricter than the 30-days-or-longer term Gov. Code § 66315 lets a city impose on ordinary ADUs and matches the longer-than-30-days rule state law imposes on state-exempt units and JADUs (§§ 66323(e), 66333(g)). ADUs and JADUs may not be sold separately (B.2.a); the code omits the § 66341 qualified-nonprofit exception that state law still guarantees, and Chapter 20.503 contains no § 66342 condominium option.