Accessory dwelling unit contractor san diego — Ontario, CA

Last updated: September 24, 2026

What affects the price

Building an ADU involves variables that shift your total investment. The footprint size and complexity of the architectural design are primary factors. Are you planning a detached unit that requires new utility trenching, or is this a garage conversion that uses existing plumbing? Site accessibility, soil conditions, and your choice of finishes—like luxury flooring versus standard options—also play significant roles. Permitting fees vary widely depending on your local municipality and current zoning requirements. Exact pricing confirmed free on the call.

About this service

In San Diego, a contractor must be well-versed in specific state-wide ADU mandates and local coastal commission rules. You need a specialized contractor here to navigate the unique topography and strict permitting requirements common in the region. Whether you are building in a flat neighborhood or on a hillside, having a pro who knows San Diego's specific structural and safety codes is essential for a successful, approved, and long-lasting backyard project.

Frequently asked in Ontario

Also serving nearby: Chino · Rancho Cucamonga · Jurupa Valley · Pomona · Fontana

All cities in California →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of Ontario — population 182,457; about 3,650 residents per square mile across 50.0 sq mi. ZIP codes covered include 91758, 91761, 91762, 91764.

Neighborhoods served in Ontario: Euclid Avenue, North Ontario, South Ontario, Central Ontario, Archibald Ranch — and every surrounding area.