Adu permit — San Jose, 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.

Frequently asked in San Jose

Also serving nearby: Burbank · Santa Clara · Sunnyvale · Fremont · Hayward

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

Service area details

Serving all of San Jose — population 969,655; about 5,449 residents per square mile across 177.9 sq mi. ZIP codes covered include 95025, 95101, 95103, 95106, 95108, 95109, 95110, 95111.

Neighborhoods served in San Jose: Willow Glen, Almaden Valley, Campbell, Saratoga, Santa Clara, Milpitas — and every surrounding area.