// San Juan Capistrano

ADU Construction in San Juan Capistrano

Spacious equestrian and rural-residential lots provide ample room for detached ADUs, strong demand from families drawn to top-rated Capistrano Unified schools, Metrolink commuter rail access, and a unique small-town character that commands premium rental rates in south Orange County.

San Juan Capistrano is one of Orange County's most distinctive cities, anchored by the historic Mission San Juan Capistrano — the birthplace of Orange County — and the surrounding Los Rios Historic District, the oldest continuously occupied residential neighborhood in California. The city's rural-residential character sets it apart from the master-planned communities to the north, with equestrian-zoned neighborhoods featuring generous lots of 10,000 to 20,000+ square feet along streets like Paseo Adelanto and Calle Arroyo. The annual Return of the Swallows celebration draws visitors each March, and the Capistrano Depot anchors a walkable downtown with independent restaurants and galleries. San Juan Capistrano sits along the Metrolink Orange County Line, providing commuter rail access to Irvine, Laguna Niguel, and Los Angeles. Major employers in the surrounding area include the Capistrano Unified School District, St. Margaret's Episcopal School, and the equestrian and agricultural industries that define the local economy.

Zoning & requirements

Setbacks
4-foot minimum from rear and side property lines for new detached ADUs. Conversions of existing structures (barns, guest houses, garages) are exempt from setback requirements. Properties within the Los Rios Historic District may require additional design review for street-facing facades.
Height
Up to 16 feet for single-story detached ADUs. Up to 25 feet for two-story ADUs per state law (AB 1332) in qualifying residential zones.
Parking
One parking space per ADU may be required. Exempt if within 0.5 miles of the San Juan Capistrano Metrolink station, within one block of a car-share vehicle, or if the ADU is a conversion of existing space.
Lot Size
10,000–20,000+ sqft in equestrian-zoned neighborhoods. Standard residential lots range from 6,000–10,000 sqft. No minimum lot size required by state law to build an ADU.
Owner Occupancy
No owner-occupancy requirement for ADUs (made permanent by AB 976 in 2025).
Additional Notes
ADUs under 750 sqft are exempt from impact fees. Properties in the Historic Town Center Plan area or Los Rios Historic District may require design compatibility review — this is limited to objective standards and cannot block an otherwise compliant ADU. Equestrian-zoned properties should verify that ADU placement does not conflict with existing stable setbacks or riding easements.

How to permit your ADU in San Juan Capistrano

01

Verify zoning & historic overlays

Confirm your property's zoning on the city's GIS map. Check whether your parcel falls within the Historic Town Center Plan, Los Rios Historic District, or an equestrian overlay zone — each may carry additional objective design standards for ADUs.

02

Design your ADU

Create architectural plans including site plan, floor plan, elevations, structural, mechanical, electrical, and plumbing. For equestrian properties, show existing structures (stables, arenas) and riding easements. In the Historic District, design facades to complement the adobe and early-California architectural character.

03

Submit plans to Development Services

Submit your complete plan set to the Development Services Department. Include Title 24 energy compliance, soils report (especially important in hillside areas near Ortega Highway), and any required septic or sewer connection documentation.

04

Plan check review (60-day)

The city reviews plans for compliance with building codes and ADU regulations. State law mandates a 60-day maximum review period for compliant ADU applications. Historic District properties may require concurrent review by the Cultural Heritage Commission under objective standards only.

05

Build & inspect

Once permitted, begin construction with your licensed contractor. Schedule required inspections at each milestone — foundation, framing, rough mechanical/electrical/plumbing, insulation, and final. Equestrian-area builds should coordinate construction vehicle access to avoid impacting horse trails.

06

Final inspection & occupancy

Request final inspection from the Building Division. Once passed, receive your Certificate of Occupancy. Your ADU is now legal to rent or occupy.

City of San Juan Capistrano Development Services Department • Fees: $6,000–$14,000 total (plan check, building permit, school fees). Impact fees waived for ADUs under 750 sqft. • Timeline: 4–8 weeks for plan check. 60-day maximum review required by state law.

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