ADUs & Additions in North Tustin

OC Public Works, OC Development Services, Building and Safety. North Tustin is unincorporated, so building and grading permits come from the County's Building and Safety division under the Orange County Grading and Excavation Code and Zoning Code. A pool may not be built within three feet of a property line or an ultimate vehicular right-of-way, or inside the corner sight areas at driveways and street intersections, and an accessory structure inside a required setback is held to 12 feet in height, or 8 feet within three feet of a property line. One guesthouse is allowed per building site, with no kitchen and no rental; at 640 square feet or less it needs no discretionary permit, while a larger one needs a site development permit on a site of an acre or more and a Zoning Administrator use permit on a smaller site. Accessory dwelling units go through a ministerial permit, and a newly built unit is capped at 1,200 square feet. Buildings in the Very High Fire Hazard Severity Zones adopted by the Board of Supervisors in Ordinance 25-015 on August 26, 2025 must be built with the fire-resistive features of California Building Code Chapter 7A or California Residential Code Section R327. We prepare the drawings, make the submittal and handle plan-check corrections ourselves, so you are not the one chasing plan check.

Most of North Tustin is zoned E4 Small Estates under the County Zoning Code, a district intended for neighborhoods where open space and deep setbacks predominate. The base E4 standards set a 10,000 square foot minimum building site, a 30-foot front setback from the ultimate street right-of-way, a 25-foot rear setback, side setbacks of 10 percent of the site's average width up to 20 feet, a 35-foot height limit and a 35 percent cap on building site coverage. The zoning map raises those minimums in places: land around Lemon Heights is largely 125-E4-20000, meaning a 125-foot minimum width and a 20,000 square foot minimum site, much of Cowan Heights is E4-20000, and Panorama Heights is mostly 100-E4. A smaller part of the community falls under the North Tustin Specific Plan instead, which carries its own district standards. One local condition that shapes the work: On CAL FIRE's Local Responsibility Area map dated March 24, 2025, a band along the community's eastern edge, near Cowan Heights and Lemon Heights, is Very High Fire Hazard Severity Zone, with smaller Moderate and High areas nearby, while most of North Tustin is mapped non-wildland.

All of it, including Lemon Heights, Cowan Heights, Panorama Heights and Red Hill. Our crews run every job out of our Cahuenga Pass base in Los Angeles, with our own people on site.

Detached ADU: generally $150,000 to $400,000+ across Southern California. What moves it is square footage, finish level, utility runs, and site access; garage conversions typically run well below a ground-up detached build. We give line-item pricing after seeing the site rather than quoting a number over the phone.

Plan a realistic year. Design and engineering typically take one to three months, city plan check and corrections add several more, and construction usually runs four to eight months depending on size and site access.

Usually yes, and often substantially, because the foundation, walls and roof already exist. The trade-offs are that you lose the garage, and older slabs and framing sometimes need upgrading to meet current code.

California ADU law is designed to allow long-term rental, and an ADU is one of the few ways to add rentable square footage to a single-family lot. Short-term rental rules vary by city, so confirm your local ordinance before counting on that income.

Yes. Plans, engineering, Title 24 and the city submittal are all handled in-house, including responding to plan-check corrections. That is a service we sell on its own, so it is not something we hand off.