Looking for accessory dwelling unit companies in San Jose, CA? Call AccessoryDwellingUnit Solutions for a contact a provider — no obligation. Licensed adu builders serve San Jose and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total budget. The biggest factor is whether you choose a prefabricated unit or a custom build on-site. Site preparation is also significant; if your land requires extensive grading, utility trenching, or foundation work, costs will climb. Your choice of finishes—like kitchen cabinetry, flooring, and siding materials—also shifts the bottom line. We help you navigate these variables to find a setup that fits your property. Exact pricing confirmed free on the call.

About this service

ADU companies offer end-to-end solutions, often handling everything from the first sketch to the final walk-through. You need these companies if you prefer a streamlined experience where one firm takes responsibility for design, permitting, and construction. They are ideal for homeowners who want to minimize the stress of managing multiple vendors and prefer a turnkey approach to adding a secondary residence to their property.

Frequently asked in San Jose

What are the disadvantages of ADUs?

While ADUs offer many benefits, potential disadvantages include upfront construction costs and potential impacts on your existing yard space. You'll also need to consider how it affects your property's privacy and utilities. Understanding these factors upfront with a professional is key to a successful project in San Jose.

How much does an ADU cost in California?

The cost of an ADU in California, including San Jose, varies significantly based on size, materials, and site preparation. Factors like foundation work, utility connections, and finishes all influence the final price. A detailed quote from a qualified professional is the best way to get an accurate cost estimate for your specific project.

What are the rules for ADUs in California?

California has state laws that streamline ADU approvals, but local San Jose ordinances also apply. These rules cover things like minimum lot size, setbacks, and parking requirements. Consulting with a local expert familiar with both state and San Jose regulations is crucial for compliance.

Is an ADU allowed in Maryland?

California has offered various programs and grants to incentivize ADU development, including some that helped offset costs. The specifics and availability of such grants can change, so it's important to research current programs. A professional can often advise on potential funding opportunities relevant to your San Jose project.

How do I start the ADU process in San Jose?

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

All cities in California →

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

Service area details

969,655residents

5,449per sq mile

8ZIP codes served

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: Downtown San Jose, Willow Glen, Almaden Valley, Berryessa, Rose Garden — and every surrounding area.