ADU rules in Stockton

Detached ADUs are allowed on any lot in a zone that allows single-unit or multi-unit dwellings and has an existing or proposed primary dwelling (SMC 16.80.310.B; Table 2-2 in 16.20.020 defers to 16.80.310), which covers the RE, RL, RM and RH residential zones and the commercial zones that allow multi-unit housing. Section 16.80.310, restated in full by Ord. 2026-05-12-0901 (adopted May 12, 2026), allows one detached new-construction ADU on a single-unit lot (combinable with a JADU), up to eight detached ADUs on a lot with existing multi-unit development (never more than the number of existing units) and two on a lot with proposed multi-unit development, tracking Gov. Code 66323(a)(2) and (a)(4). Detached units need only 3-foot side and rear setbacks, more generous than the 4-foot maximum the state lets cities require, and may be 16 feet tall for one story or 25 feet for two stories. On a lot split under SB 9 (Gov. Code 66411.7) only one ADU per resulting parcel is allowed (C.7).

Attached additions, internal conversions and conversions of accessory structures are allowed: 16.80.310.C.4 allows one attached ADU and/or one JADU inside the primary dwelling on a lot with an existing or proposed single-unit dwelling, and C.6 adds, 'in addition to' the attached and detached allowances, one ADU per lot within the converted space of an existing single-family dwelling or accessory structure under Gov. Code 66323. On lots with existing multi-unit buildings, at least one ADU and up to 25 percent of the existing unit count may be created in non-livable space such as storage rooms, attics, basements or garages (C.1). Read literally, the code therefore allows an attached ADU, a detached ADU, a conversion ADU and a JADU on one single-family lot, while the city's June 2026 ADU Guide describes one attached, one detached and one JADU. JADUs (up to 500 sq ft of interior livable space inside a single-unit home, with an efficiency kitchen and a separate entrance) are limited to one per lot zoned for single-unit dwellings (H).

SMC 16.80.310.D.4 caps a detached ADU at 1,200 sq ft of floor area, excluding any enclosed parking, exterior stairs or similar non-habitable features, and an attached ADU at 50 percent of the existing primary dwelling or 850 sq ft, whichever is greater (so there is no fixed ceiling on a large home); a JADU is capped at 500 sq ft of interior livable space. Gov. Code 66321(b)(2), as amended by SB 543, bars any maximum below 850 sq ft of interior livable space, or 1,000 sq ft for a unit with more than one bedroom, and HCD's March 2026 handbook applies that floor to percentage caps on attached units; because Gov. Code 66325 makes state law supersede a conflicting ordinance, a multi-bedroom attached ADU may reach 1,000 sq ft of interior livable space even where half the home is smaller, and the local caps (stated as floor area, a term the Title 16 glossary does not define) cannot push a unit below those floors. Conversions of existing space and the other Gov. Code 66323 units sit outside the local caps (the opening clause of 16.80.310.D and 66323(b)), and Stockton does not use the state's option to cap the single-family detached unit at 800 sq ft. Heights (D.3): attached 25 feet or the zone limit and two stories; detached 16 feet for one story and 25 feet for two stories, 18 feet within half a mile of a major transit stop or with a multistory multi-unit building, plus 2 feet for a roof pitch matching the main house.

No: SMC 16.80.310.G states that owner occupancy is not required on a property with an ADU, matching Gov. Code 66315. For JADUs, H.6 (rewritten by Ord. 2026-05-12-0901) requires the owner to live in the house or the JADU only when the JADU shares sanitation facilities with the house, and never when the owner is a governmental agency, land trust or housing organization, tracking Gov. Code 66333(b) as amended by AB 1154 effective January 1, 2026; before May 2026 the city required it for every JADU not owned by a governmental agency, land trust or housing organization. A JADU still needs a recorded deed restriction barring separate sale and fixing its size and attributes (H.7). The city's ADU page (last updated June 1, 2026) and its June 2026 ADU Guide still say JADU owner occupancy is always required and recorded in the deed restriction; that wording predates the May 2026 amendment.

Stockton requires no off-street parking for any ADU (SMC 16.80.310.E.1) and no additional parking for a JADU (H.5); the city's ADU Guide traces the parking waiver to its 2018 ADU ordinance. Parking that an owner chooses to provide may be uncovered, covered, enclosed or tandem, must be paved and reached from a paved driveway, and may exceed the front-yard paving limit of 16.64.090.A.2 (E.2). When a garage, carport or covered parking structure is demolished to build an ADU, no replacement parking is required (E.3), consistent with Gov. Code 66314(d)(11). The Magnolia historic overlay's general rule of one covered space per dwelling unit (16.28.060.G) is displaced for ADUs by 16.80.310.E.1 and by Gov. Code 66322(a)(2), which bars parking standards for ADUs in an architecturally and historically significant district.

Ministerial: under SMC 16.80.310.A the Review Authority issues a ministerial building permit for an ADU or JADU without discretionary review or a hearing, with zoning compliance checked through ministerial planning review inside the building permit process. Ord. 2026-05-12-0901 added the Gov. Code 66317 clocks: a written completeness determination within 15 business days and action within 60 days of a complete application (tolled at the applicant's request, or deferred when filed with a new house), with written comments on any denial. The city offers free permit-ready studio (469 sq ft), one-bedroom (625 sq ft) and two-bedroom (746 sq ft) plans, which are not an option in FEMA Special Flood Hazard Areas. The overlay chapters still require a Commission use permit for any new structure in the Channel area overlay (16.28.040.C), a certificate of appropriateness for new construction in the Magnolia historic district (16.28.060.D.3; 16.220.060) and design review in the design review overlay (16.28.050.C), and the pre-2025 ADU text that expressly exempted ADUs from the first two is gone; Gov. Code 66317(a)(1) nonetheless requires ministerial approval notwithstanding any local use permit ordinance, so those steps can only operate as objective, staff-level review for an ADU.

SMC 16.80.310.F lets an ADU or JADU be rented for a term of at least 30 days, which Gov. Code 66315 permits for standard ADUs ('rentals of terms 30 days or longer'); for JADUs and Gov. Code 66323 state-exempt units, 66333(g) and 66323(e) require terms longer than 30 days, so those units need a 31-day minimum. Stockton has no short-term rental ordinance (a 2022 draft licensing chapter, 5.82, was never adopted), and stays of 30 consecutive days or less in any dwelling owe the 8 percent transient occupancy tax (Chapter 3.28). A rented ADU brings the parcel into the Residential Rental Inspection Program (Chapter 8.32: registration when the parcel's area is active, inspection at least every five years or self-certification, a fee set by resolution), and a business license is needed for three or more rental units (5.08.030(22)). Since Ord. 2025-06-03-1601 (June 3, 2025) Stockton has opted in to the Gov. Code 66342 regime: an ADU may be sold separately as a condominium under the Davis-Stirling Act and the Subdivision Map Act, after a safety inspection, with every lienholder's consent, notice to utilities and, inside an existing homeowners association, the association's written authorization (F.1); sale to a qualified buyer under the 66341 nonprofit model is also allowed (F.1.j), while a JADU can never be sold separately (H.7).