ADU rules in Pittsburg

A detached ADU is allowed on any lot with a single-family or multifamily home in every residential district (RR, RS-40, RS-10, RS-6, RS-5, RS-4, RM, RMD, RH and RHD) and in planned development districts; the use tables list it as L-107, 'Permitted, subject to the requirements of PMC § 18.50.300 through § 18.50.315', and the OS and GQ tables carry the same entry. Schedule 18.50.315 (Ord. 23-1510, 2023) still allows only one ADU per single-family lot (attached or detached) plus a JADU, and only two detached ADUs beside a multifamily building; both counts yield to Gov. Code § 66323(a), which requires ministerial approval of a detached new-construction ADU of up to 800 sq ft in combination with a conversion ADU and a JADU on a single-family lot, and of up to eight detached ADUs (never more than the existing units) on a lot with an existing multifamily building. The Mixed Use (M) and commercial district tables allow multifamily housing but have no ADU row, and Hillside Planned District lots need a hillside planned development permit before any building permit (§ 18.56.050); state law (§§ 66314, 66317, 66323) controls in both cases.

Attached ADUs (additions, and conversions of space inside the home or an existing accessory structure) are allowed on the same terms as detached units, and a JADU of up to 500 sq ft inside the walls of a single-family home is permitted with a single-family use in all zoning districts. On multifamily lots the code allows conversion ADUs in space not used as livable area up to 25 percent of the existing units; § 66323(a)(3) also guarantees at least one. Schedule 18.50.315 describes one attached ADU per lot plus a JADU, but under § 66323(a)(1) and (a)(2) a conversion ADU and a JADU can be combined with a detached state-exempt unit; HCD's 12-22-2021 findings had already told the city that the table's unit counts understated the permissible combinations.

Schedule 18.50.315 caps a detached ADU that is not a statewide exemption unit at 1,200 sq ft, and an attached one at the lesser of 50 percent of the primary dwelling's floor area or 1,200 sq ft, while always allowing 850 sq ft, or 1,000 sq ft with more than one bedroom, regardless of the 50 percent limit. A 'Statewide Exemption ADU' of up to 800 sq ft is allowed in either form and is exempt from lot coverage and FAR; JADUs are capped at 500 sq ft. Detached units may be 16 ft tall, or 18 ft within one-half mile walking distance of a major transit stop or high-quality transit corridor (plus 2 ft to match the main roof pitch) or on a lot with a multistory multifamily building; attached units may reach 25 ft, and a 3:12 minimum roof pitch applies. The schedule states sizes in plain square feet while state law measures the 850/1,000 sq ft floors and the 800 sq ft allowance in interior livable space (§ 66321(b)), and conversions under § 66323(a)(1) carry no size cap beyond the 150 sq ft expansion allowance. If the 2023 ordinance were treated as void under § 66316 (see caveats), the state defaults would apply: 1,200 sq ft detached and attached 50 percent of the existing home with no 1,200 sq ft ceiling (§ 66314(d)(4)-(5)).

Nothing in Article IV requires an owner to live on a lot with an ADU, and Gov. Code § 66315 bars such a condition. For JADUs, § 18.50.310(F) still says the primary dwelling and JADU 'shall be separately occupied only if the owner occupies one of the units' and requires a recorded deed restriction (owner occupancy is waived when the owner is a governmental agency, land trust or housing organization). Since 1-1-2026, Gov. Code § 66333(b) allows owner occupancy only when the JADU shares sanitation facilities with the home, so a JADU with its own bathroom carries no owner-occupancy requirement despite the local text. The city's JADU deed restriction form (created March 2022) still prints the universal rule; the pending AP-26-0067 rewrite would adopt the shared-sanitation test.

Schedule 18.50.315 requires one space for an attached or detached ADU, which may be tandem with the main home's required parking, and none for a JADU. No space is required within one-half mile walking distance of a public transit stop (bus stops count), in an architecturally and historically significant historic district, for a unit entirely within the existing or proposed home or an existing accessory structure that adds no floor area, where on-street parking 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 on the same lot. A garage, carport or covered parking structure demolished or converted for an ADU need not be replaced, and state law extends that to uncovered spaces (§ 66314(d)(11)). The flat one-space rule exceeds the state ceiling of one space per unit or per bedroom, whichever is less (§ 66314(d)(10)(A)), so a studio arguably owes none, and units built under the § 66323 state-exempt pathway owe none (§ 66323(b)).

§ 18.50.310 says a compliant ADU or JADU application 'shall be processed ministerially' through the staff zoning approval that precedes a building permit (§ 18.32.010(B)), and an application is deemed approved if not acted on within 60 days of being deemed complete; the residential use tables list ADUs as permitted (L-107), with no use permit or hearing. State law adds the 15-business-day completeness check and the 60-day ministerial clock (§ 66317). Older general paths could be read to reach ADUs: § 18.36.100 lets the city planner refer a doubtful single-family building permit to the Planning Commission, § 18.36.200 sends building designs in other districts to the Commission, and Hillside Planned District lots need a hillside planned development permit (§ 18.56.050); none is ADU-specific, and § 66317(a)(1) bars discretionary review or a hearing for an ADU permit. The subjective design findings in § 18.50.310(D) and the schedule's requirement that a detached unit 'be in harmony with the primary dwelling unit or convey the appearance of a single-family home' exceed the objective-standards limit of § 66314(b)(1).

§ 18.50.310(H) requires an owner who rents an ADU or JADU to register it with the city's residential rental inspection program (PMC Chapter 15.91: registration and annual fees set by council resolution, periodic inspections, three-year self-certification for well-kept properties) and provides that no ADU or JADU 'shall be rented for a term of 30 days or less'. That 31-day floor matches the longer-than-30-day terms state law requires for JADUs (§ 66333(g)) and state-exempt units (§ 66323(e)), but it is one day stricter than § 66315 allows for ordinary ADUs (terms of 30 days or longer). Pittsburg has no short-term rental ordinance; the code has no short-term or vacation rental provisions, so the 30-day bar is the operative short-term rule for ADUs. Units may be rented but not sold separately except to a qualified nonprofit under § 18.50.310(A) (citing legacy § 65852.26, now § 66341); the JADU deed restriction bars separate sale, and the city has not opted into § 66342 ADU condominiums.