San Jose ADU Permit & Building Guide
Building an Accessory Dwelling Unit (ADU) in San José is one of the best ways to unlock the hidden potential of your property. At Apex Homes, we specialize in designing and building ADUs that provide extra living space, stable rental income, and long-term property value. With pre-approved plans and streamlined permitting, many of our clients are able to complete their ADU in as little as five months.
San Jose ADU Regulations
The City of San José allows ADUs on both single-family (R-1 zoning) and multi-family (R-2 zoning) lots, but the rules differ slightly.
For single-family lots, homeowners may build one detached or attached ADU plus one Junior ADU (JADU). Detached or attached ADUs can be up to 1,200 square feet for lots larger than 9,000 sq. ft., or up to 1,000 square feet for smaller lots. JADUs are capped at 500 square feet with no lot size requirement.
Setbacks are straightforward: one-story ADUs may be built with a zero-foot setback, while two-story ADUs require at least four feet. Detached units may be up to 25 feet tall and two stories, with at least six feet of separation from the main home.
On multi-family lots, one detached or attached ADU is allowed, following the same size rules as single-family lots. The same setback, height, and separation requirements apply.
The San Jose ADU Permitting Process
The permitting process in San José is relatively efficient, especially when using pre-approved designs. The first step is to confirm your property’s zoning and select a compliant floor plan. Submitting a pre-approved ADU plan can save significant time by eliminating the design review process.
Once you’ve chosen a design, you’ll need to prepare and submit site-specific documents, such as plot plans, elevations, and structural details, through the San José Permit Center. Depending on the scope of work, permits are typically issued within two to four months. Using a pre-approved plan can shorten this timeline to just a few weeks.
Pre-Approved ADU Plans in San Jose
San José maintains a library of pre-approved ADU floor plans that have already been reviewed for zoning and building code compliance. When combined with accurate site-specific documents, these plans enable expedited permitting, often within one week.
At Apex Homes, we offer six pre-approved layouts in San José, ranging from one-bedroom cottages to larger three-bedroom designs.
Why Build an ADU in San Jose?
San José, the heart of Silicon Valley, offers some of the strongest demand for rental housing in California. A well-built ADU here can generate $2,000 to $3,500 per month in rental income, depending on size, layout, and amenities. For many homeowners, that means extra cash flow to offset mortgage payments or increase monthly savings.
Adding a legal ADU doesn’t just bring income, it also boosts property value. In San José, homes with ADUs typically see a 20–30 percent increase in resale value, making them an attractive long-term investment.
Beyond the financial returns, ADUs also create flexibility for family living. They provide private, independent space for aging parents, adult children moving back home, or live-in caregivers. Many San José homeowners also use ADUs as home offices, creative studios, or comfortable guest quarters.
For more detailed information or specific guidance, we can book a free consultation with an Apex Home ADU expert. Let us help you transform your property with a thoughtfully planned ADU today!