ADU rules in San Bernardino

Detached ADUs are allowed on residential lots citywide: Table 04.01 lists Accessory Dwelling Unit as P (permitted) in all eight residential zones (RE, RL, RS, RU, RM, RMH, RH, RSH), and SBMC 19.04.030(2)(P), restated in full by Ord. MC-1659 (adopted February 4, 2026, effective March 6, 2026), sets two tracks. Class 1 units follow Gov. Code 66323 in any residential or mixed-use zone: one new detached ADU of up to 800 sq ft of livable space with 4-foot side and rear setbacks on a single-family lot (combinable with a conversion ADU and a JADU), and on multifamily lots up to two detached ADUs with a proposed building or up to eight, never more than the existing unit count, with an existing one. Class 2 units follow Gov. Code 66314-66322 on any lot zoned for single-family or multifamily use and must meet the local standards of subsection 7: 16-foot height and one story, 4-foot side and rear and 25-foot front setbacks, 45 percent FAR, 50 percent lot coverage, 50 percent minimum open space, matching materials and roof slope, and evergreen screening. HCD's April 22, 2026 findings letter says several of those Class 2 rules, and the ordinance's silence on pairing a Class 2 ADU with the Class 1 units, violate state law.

Attached and conversion ADUs are allowed on the same lots. As Class 1 units, one ADU may be converted within the existing or proposed space of a single-family home or an existing accessory structure (plus up to 150 sq ft for ingress and egress) together with one JADU, and on multifamily lots at least one converted ADU, up to 25 percent of the existing units, may be built in non-livable space such as storage rooms, attics, basements or garages. Class 2 attached additions may reach 25 feet or the zone's height limit, whichever is lower, and two stories, and are capped at 50 percent of the existing primary dwelling's floor area, though never below 800 sq ft of interior livable space. JADUs (up to 500 sq ft of interior livable space inside a single-family structure, with an efficiency kitchen) are allowed only on lots zoned for single-family residences.

For Class 2 ADUs, 19.04.030(2)(P) 7.a caps size at 850 sq ft of interior livable space for a studio or one-bedroom unit and 1,000 sq ft for two or more bedrooms, with attached units further limited to 50 percent of the existing home; the percent cap, 45 percent FAR, 50 percent lot coverage, 50 percent open space and the 25-foot front setback may not push an ADU below 800 sq ft (7.a.iii). The Class 1 state-exempt detached unit is capped at 800 sq ft of livable space and a JADU at 500 sq ft. Heights (6.b): 16 feet for detached units, 18 feet within half a mile walking distance of a major transit stop or high-quality transit corridor plus 2 feet to match the main roof pitch, 18 feet on a lot with a multistory multifamily building, and 25 feet (or the zone limit) and two stories for attached units, while Class 2 detached units are held to one story (7.k). These caps sit exactly at the state floors in Gov. Code 66321(b) as amended by SB 543, but HCD found the one-story limit, the 'above grade' qualifier on the multifamily height and the lowest-floor height measurement unlawful, and if MC-1659 is void under Gov. Code 66326(d) the state defaults in 66314(d)(4)-(5) govern instead (attached up to 50 percent of the home, detached up to 1,200 sq ft).

No: 19.04.030(2)(P) 6.g.i states that ADUs are not subject to an owner-occupancy requirement, matching Gov. Code 66315. For JADUs the owner must live in the main home or the JADU only when the JADU shares sanitation facilities with the main home; the requirement falls away when the JADU has its own bathroom or the property is owned by a governmental agency, land trust or housing organization (6.g.ii), tracking Gov. Code 66333(b) as amended by AB 1154 effective January 1, 2026. A JADU deed restriction (no separate sale, approved size and attributes) must be recorded before the JADU's certificate of occupancy (6.h). The city's posted February 2025 copy of Chapter 19.04 still prints the superseded MC-1645 clause subjecting every JADU to owner occupancy.

For Class 2 ADUs, 19.04.030(2)(P) 7.g requires one off-street space per ADU or per bedroom, whichever is less, which may sit in setback areas or be tandem; no space is required within half a mile walking distance of public transit (defined in 3.k to include any fixed-route, set-fare bus stop), in an architecturally and historically significant district, for a unit within the home or an accessory structure, where on-street permits are not offered to the occupant, within one block of a car-share stop, or when the ADU is filed with a new home that meets one of those tests. Subsection 7 does not apply to Class 1 (Gov. Code 66323) units or JADUs, and garage, carport or driveway spaces removed for an ADU never need replacement (7.g.iii; Gov. Code 66314(d)(11)), which overrides the general replacement-garage rule of 19.24.030(7). This is a reversal: the January 2025 text (Ord. MC-1645) had no ADU parking requirement, while MC-1658U (December 3, 2025) and MC-1659 reinstated one space, matching the state ceiling in Gov. Code 66314(d)(10); HCD's April 2026 findings did not question it.

Every ADU and JADU needs an ADU permit and a building permit, both ministerial: 19.04.030(2)(P) 4 promises a completeness determination within 15 business days, approval or denial within 60 days of a complete application without discretionary review or a hearing, and written appeals to the Planning Commission decided within 60 business days, tracking Gov. Code 66317 as amended by SB 543. Subsection 10 adds a conditional use permit route for an ADU that does not meet the objective standards; HCD's Finding 16 says no discretionary review is authorized and the city must review all ADU applications ministerially. The city's ADU page offers two pre-approved detached plans (Morning Glory, 462 sq ft; Carnation, 738 sq ft) that still need Planning pre-approval before Building and Safety submittal, and quotes 15 to 20 business days for a first plan review.

ADUs and JADUs may be rented separately but not for a term shorter than 30 days, a ban that applies regardless of when the unit was created (19.04.030(2)(P) 6.d); state law independently requires terms longer than 30 days for Class 1 units (Gov. Code 66323(e)) and JADUs (66333(g)), so even a 30-day rental is out for those units. An ADU may not be sold or conveyed separately from the lot and primary dwelling except under the Gov. Code 66341 qualified-nonprofit path (6.e); the city has not adopted a Gov. Code 66342 ADU-condominium ordinance, which HCD encouraged in Finding 7. Citywide, the SBMC does not specifically address short-term rentals (June 17, 2026 staff report): the council introduced a ban (Ord. MC-1661) 4-3 on April 15, 2026, then voted 4-3 on June 17, 2026 to deny its adoption and 6-1 to have staff return with a regulatory program, which had not reached an agenda through September 16, 2026.