Accessory dwelling unit companies — Fremont, CA

Last updated: September 24, 2026

What affects the price

Building an ADU is a custom project, so costs vary based on your specific choices. Site conditions are the biggest factor; if your land requires significant grading, utility extensions, or foundation work, those expenses add up quickly. Choosing high-end finishes, custom cabinetry, or complex roof lines will also push the budget higher compared to a standard design. Prefabricated units often offer predictable costs, while custom site-built structures allow for more flexibility but can be harder to estimate upfront. Exact pricing confirmed free on the call.

About this service

Frequently asked in Fremont

Also serving nearby: Sunnyvale · Santa Clara · Burbank · Hayward · San Jose

All cities in California →

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

Service area details

Serving all of Fremont — population 226,208; about 2,896 residents per square mile across 78.1 sq mi. ZIP codes covered include 94536, 94537, 94538, 94539, 94555.

Neighborhoods served in Fremont: Warm Springs, Niles, Centerville, Mission San Jose, Ardenwood — and every surrounding area.