ADU rules in San Juan Capistrano

Detached ADUs are allowed beside a single-family or multifamily home under two ministerial tracks in SJCMC § 9-3.501.1 as restated by Ord. 1136 (adopted 5-19-2026): a Type 1 state-exempt unit (Gov. Code 66323) of up to 800 sq ft of livable space with 4-foot side and rear setbacks, which may be combined with a converted ADU and a JADU, or up to eight detached units beside an existing apartment building (two beside a proposed one, never more than the existing unit count); or a larger Type 2 local-track unit of up to 850 or 1,000 sq ft. Detached units may be 16 feet tall (18 feet within a half mile of a major transit stop, plus 2 feet to match the home's roof pitch, and 18 feet beside a multistory apartment building). Table 3-1 lists the ADU use as permitted in the RA, HR, RSE-40,000, RSE-20,000, RS-10,000, RS-7,000, RG-7,000, RS-4,000, RG-4,000 and MRD-4,000 districts (the last only on lots of 6,000 sq ft or more) but shows dashes for RM, VHD, MHP and PRD; the ADU section itself allows Type 1 units in any single-family or multifamily zoning district and Type 2 units wherever single-family or multifamily residential use is allowed, as Gov. Code 66314 and 66323 require, so the table entries and the MRD lot gate do not control. A Type 2 detached unit may not be built or graded within 200 feet of a General Plan designated ridgeline.

Attached and internal ADUs are allowed. Under the Type 1 state-exempt track, one ADU can be created within the space of an existing or proposed single-family home or an existing accessory structure such as a garage (plus up to 150 sq ft for an entry), alongside one JADU of up to 500 sq ft inside the home; in existing multifamily buildings, non-livable space such as storage rooms, attics, basements or garages can be converted into at least one ADU and up to 25 percent of the existing unit count. New attached additions use the Type 2 track: 850 sq ft (studio or one bedroom) or 1,000 sq ft (two or more bedrooms) of interior livable space, further limited to 50 percent of the existing home's floor area but never below 800 sq ft, and no taller than 25 feet or the zone's height limit, whichever is lower, with at most two stories. JADUs are limited to lots zoned for single-family residences, as Gov. Code 66333(a) provides.

Type 2 (local-track) ADUs, attached or detached, are capped 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, exactly the floor Gov. Code 66321(b)(2) allows and below the 1,200 sq ft detached default in 66314(d)(5); a new attached ADU is also held to 50 percent of the existing home's floor area. The 0.35 lot coverage limit, the 30-foot front setback and the 50 percent rule can never push a Type 2 unit below 800 sq ft of interior livable space, and the city imposes no FAR or open-space limits on ADUs. The Type 1 state-exempt detached unit is limited to 800 sq ft of livable space with 4-foot setbacks, conversions of existing space are not capped (accessory-structure conversions may add 150 sq ft for an entry), and a JADU is at most 500 sq ft. Heights are 16 feet for a detached unit (18 feet near a major transit stop or beside a multistory apartment building, plus 2 feet for a matching roof pitch) and 25 feet or the zone limit, whichever is lower, for an attached unit, matching the floors in Gov. Code 66321(b)(4).

Section 9-3.501.1(f)(6)(A) states that ADUs are not subject to an owner-occupancy requirement, as Gov. Code 66315 requires. For JADUs, an owner must live in the main home or the JADU only when the JADU shares sanitation facilities with the main home, and never when the property is entirely owned by a government agency, land trust or housing organization, mirroring Gov. Code 66333(b) as amended by AB 1154; Ord. 1136 replaced the Ord. 1127 text that applied JADU owner occupancy universally and tied the ADU exemption to units built since 2020. A JADU still needs a recorded deed restriction (no separate sale, size and attributes) before its certificate of occupancy. The city's JADU deed-restriction template (DocumentCenter 4580, last modified May 2025) still has every JADU owner covenant to live on site; that clause is stale against both the code and state law, while the city ADU page states the shared-sanitation rule correctly.

Only Type 2 (local-track) ADUs carry a parking rule: one off-street space at least 9 by 19 feet for each ADU, which may be in a garage, carport, driveway (tandem allowed) or paved setback area, and the ADU must share the main home's driveway apron unless the fire authority requires a separate one. No space is required within a half mile walking distance of a public transit stop (the code counts any bus stop or train station with fixed routes and set fares), in the Los Rios Historical Residential District or the Mission Residential Zoning District, for a unit inside the home or an accessory structure, where on-street permits are required but not offered, within one block of a car-share stop, or for an ADU applied for together with a new home that meets one of those criteria. Type 1 state-exempt units and JADUs sit outside subsection (g) entirely, and garage or carport spaces lost to an ADU never have to be replaced. Gov. Code 66314(d)(10)(A) caps ADU parking at one space per unit or per bedroom, whichever is less, so the flat one-space rule exceeds the state cap for a studio on a plain reading.

Every ADU and JADU needs a ministerial ADU permit and a building permit, decided without discretionary review or a hearing: the city must rule on completeness within 15 business days and approve or deny a complete application within 60 days or it is deemed approved, and incompleteness findings and denials can be appealed to the Planning Commission, which decides within 60 business days. In practice Type 1 units (conversions and the 800 sq ft detached unit) get a streamlined Building Permit Review after an emailed preliminary check by Planning, while other ADUs go through a Planning Division ADU Permit Review before the building permit appointment. A unit that cannot meet the objective standards may instead seek a discretionary zone variance under § 9-2.351 (§ 9-3.501.1(j)), an optional route rather than the normal path. No part of the city is in the coastal zone (Pub. Resources Code 30168(i)), so no coastal development permit applies.

Section 9-3.501.1(f)(4) bars renting any ADU or JADU for a term shorter than 30 calendar days, whenever the unit was built, which Gov. Code 66315 allows for ordinary ADUs; for JADUs and Type 1 state-exempt units, Gov. Code 66333(g) and 66323(e) require a term longer than 30 days, so 31 days is the real minimum for those units. ADUs and JADUs may be rented but not sold or conveyed separately except through a qualified nonprofit under Gov. Code 66341, and the city has not opted into Gov. Code 66342 ADU condominiums. San Juan Capistrano has no short-term rental permit program: short-term boarding and rooming houses (lodging for fewer than 30 days for compensation) are listed only in the RM and VHD districts, and the city treats short-term lodging as prohibited in single-family districts, although a March 2026 Superior Court ruling found that position too vague to enforce in the Los Rios Specific Plan's Historic Residential district. On 5-5-2026 the Council initiated Code Amendment 26-003 (Resolution 26-05-05-02) to make short-term and long-term lodging explicitly prohibited in all single-family districts; no hearing had been held through 10-7-2026.