ADUs & Additions in Fullerton

City of Fullerton Community and Economic Development Department, Building and Safety Division. Residential permits are issued by the Building and Safety Division on the second floor of City Hall at 303 West Commonwealth Avenue, with applications filed through the city's EasyDev self-service portal and afternoon counter visits by booking only. The city's Swimming Pool and Spa Guide calls for engineered pool plans bearing the engineer's wet signature, a pre-pool inspection that checks proximity to slopes, loose fill, retaining walls and adjacent structures, a cash bond posted before construction, and continuous inspection of gunite placement. In the R-1P, R-2P and R-3P Residential Preservation Zones, work is reviewed against the city's Design Guidelines for Residential Preservation Zones, and any addition that reaches half the existing floor area or exceeds 500 square feet, or that is readily visible from the public street, goes to site plan review. The preservation zones allow accessory dwelling units but not two-unit developments or urban lot splits. We prepare the drawings, make the submittal and handle plan-check corrections ourselves, so you are not the one chasing plan check.

Single-family zoning is keyed to minimum lot size, and the standards scale with it: first-story rear setbacks from a neighboring lot run from 15 feet in zones of 7,200 square feet or less to 25 feet at 20,000 square feet and over, and maximum lot coverage steps down from 60 percent on the smallest lots to 45 percent on the largest. The preservation neighborhoods are mostly California bungalows, with many Spanish Colonial Revival homes, built between 1920 and 1940. In Pico-Carhart, where residents petitioned in 2002 for larger minimum lots, a Rural Street Overlay on parts of the neighborhood calls for recessed garage doors, a single-story element along the street and minimal disruption of natural contours. One local condition that shapes the work: The southern part of the city is flat, while the northern half rises into the West Coyote and East Coyote Hills. The city's 2026 hazard mitigation plan describes its mapped landslide zones as sparse and concentrated in the Robert E. Ward and Panorama nature preserves, with deep-seated landslide susceptibility covering the same hillsides and reaching into surrounding areas to a lesser degree.

All of it, including Upper Golden Hill, Sunny Hills, Pico-Carhart and Skyline Park. 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.