ADU rules in Hesperia

HMC 16.12.360(D)(1) allows an ADU on any lot zoned for agricultural, single-family, multifamily or mixed uses that holds an existing or proposed home, and (E)(1) lets it stand detached, including in a converted detached garage; the residential use table (HMC 16.16.085, row C) lists accessory dwelling units as an accessory use ("A") in all five residential designations (R1, R3, RR, A1 and A2). The local text still allows only one ADU plus one JADU on a single-family lot (D.3.a) and no more than two detached ADUs on a multifamily lot (D.3.b), but Gov. Code 66323(a), as amended by SB 543 from 1-1-2026, requires ministerial approval of "any combination" of a conversion ADU, one detached new-construction ADU and a JADU, and of up to eight detached ADUs beside an existing multifamily building (never more than its existing units). HCD flagged both local limits on 6-19-2025; the city's answer, Ord. 2025-05, was introduced in October 2025 but never adopted. Lots without sewer must be at least one gross acre or install an approved supplemental treatment septic system (D.10, a Lahontan Regional Water Quality Control Board rule).

Under HMC 16.12.360(E)(1) an ADU may be attached to or built within the existing or proposed home, including an attached garage, storage area or accessory structure, and on a multifamily lot it may be converted from non-habitable space. An attached ADU needs its own entrance, which may not sit on the same wall plane as the main entrance (E.3); new attached space gets 4 ft side and rear setbacks and conversions of existing space need none (E.4, E.5). JADUs of up to 500 sq ft must sit within the walls of an existing or proposed single-family home, attached garages included (B.c, F.2.c), with a separate entrance and an efficiency kitchen (F.2.d, F.2.e). The local text confines JADUs to lots zoned agricultural or single-family (D.2), while Gov. Code 66323(a)(1) requires ministerial approval of a JADU with any single-family home in a residential or mixed-use zone.

HMC 16.12.360(E)(2) caps a detached ADU at 1,200 sq ft of livable floor area (garage and accessory structures excluded) "on any parcel" and an attached ADU at 50 percent of the main home's area up to 1,000 sq ft; (E)(7) guarantees an attached or detached 800 sq ft ADU with 4 ft side and rear setbacks regardless of lot coverage or nonconformity, which is what owners of homes of 1,600 sq ft or less get (E.2 still routes those homes to subsection (E)(6), a construction-standards clause, a drafting carry-over HCD flagged in 2024). No ADU may be smaller than 150 sq ft, and JADUs top out at 500 sq ft (F.2.c). Heights track the state floors in Gov. Code 66321(b)(4): 16 ft detached, 18 ft within a half mile of a major transit stop (plus 2 ft to match the main roof pitch) or beside a multistory multifamily building, and 25 ft or two stories attached (E.8). HCD's 6-19-2025 finding 5 says units built under Gov. Code 66323 carry no local size cap (a conversion is limited only to the existing space plus 150 sq ft for access, and the up-to-eight detached units on a multifamily lot have no size limit); the city disagreed in the unadopted Ord. 2025-05, so the codified 1,200 sq ft cap still reads as covering every detached unit while state law exempts 66323 units from it.

No owner-occupancy rule applies to ADUs: Ord. No. 2024-13 (adopted 12-3-2024) deleted former subsection (D)(5), which had required the owner to live in the main home or the ADU (suspended until 1-1-2025), consistent with Gov. Code 66315. The JADU text still requires owner occupancy of one of the units in every case, through the purpose clause (F.1) and the recorded deed restriction (F.2.h(iv)), but Gov. Code 66333(b), as amended effective 1-1-2026, allows that requirement only when the JADU shares sanitation with the house. The city's April 2026 ADU/JADU application nonetheless asks the owner to certify under penalty of perjury to being "the legal owner and occupant of the primary residence," a statement Gov. Code 66315 bars as a condition for ADUs. Owner residence still matters for rental licensing, since HMC 5.72.030(A)(5) exempts ADUs that are part of an owner-occupied single-family residence from the Rental Housing Business License program.

Ord. No. 2024-13 deleted the one-space ADU parking rule (former E.8), and the residential parking table (HMC 16.20.080, Table 16.20.080(A)) has no ADU row, so no space is required for any ADU anywhere in the city. HMC 16.12.360(E)(10) says garage, carport or covered spaces demolished or converted for an ADU "do not need to be replaced," matching Gov. Code 66314(d)(11). For JADUs, Ord. No. 2025-01 (adopted 5-20-2025) struck "Additional parking shall not be required" and added (F)(2)(g): a JADU may not convert an attached garage holding the house's required parking (a two-car garage for one to four bedrooms) without a replacement enclosed garage elsewhere on the lot. Gov. Code 66334(a) bars a JADU ordinance from requiring additional parking as a permit condition and 66323(a)(1) requires ministerial approval of a JADU within existing space, so the replacement rule likely yields; HCD's 2025 review covered Ord. No. 2024-13 and has not addressed it.

HMC 16.12.360(C)(a) makes ADU review "administrative review without notice (ministerial)" under HMC 16.12.005(A)(3), a Development Review Committee decision on adopted standards with no hearing or neighbor notice, followed by a building permit; applicants file the Planning Division's ADU/JADU Planning Approval Application. Subsection (C)(b) requires the city to act within 60 days of a complete application, and Gov. Code 66317 adds the 15-business-day completeness check and deems an application approved if it is not approved or denied within 60 days. Article X labels its uses special uses (HMC 16.12.355), but Gov. Code 66317(a)(1) requires ministerial approval notwithstanding any special use permit ordinance, and the ADU text itself says applications are considered "without discretionary review or a public hearing." The Planning Commission hears appeals of Development Review Committee decisions (HMC 16.12.055).

HMC 16.12.360(D)(7) bars renting an ADU for less than 30 consecutive days, a floor Gov. Code 66315 allows for ordinary ADUs; the JADU deed restriction carries the same 30-day wording (F.2.h(iii)), while Gov. Code 66333(g) and 66323(e) require terms longer than 30 days for JADUs and state-exempt units. Hesperia has no short-term or vacation rental ordinance (none in the code; the 9-10-2026 Development Code Update workshop proposed adding one), so the 30-day rule is the operative bar on nightly rentals of ADUs. An ADU may be rented but not sold separately except through a qualified nonprofit under (D)(8) and Gov. Code 66341; the city has not opted into Gov. Code 66342 ADU condominiums. Rented residential property needs an annual Rental Housing Business License with inspection or self-certification (HMC 5.72.050 to 5.72.120), and HMC 5.72.030(A)(5) exempts "Accessory Dwelling Units which are part of a single family residence occupied by the owner."