Everything homeowners need to know about building an accessory dwelling unit in San Jose - size limits, setbacks, permits, and how the city's standards work alongside California's statewide by-right ADU law.
Last verified: August 2026
8/10 · Very ADU-friendly
1,200 sq ft
Max ADU size
16 ft
Max height
Not required
Owner-occupancy
By-right
Permit type
This page summarizes the City of San Jose's ADU regulations (San Jose Municipal Code Title 20) and California's statewide ADU law (Government Code Section 65852.2) for general reference - it is not legal advice. Regulations change; always confirm current requirements with the San Jose Development Services Permit Center before designing or applying for permits. See sources below.
Zoning & size requirements
What you're allowed to build
ADU type
Max size
Max height
Notes
Detached (new build or garage conversion)
1,200 sq ft (150 sq ft minimum)
16 ft, with some additional allowance in certain multifamily zoning districts
Front-yard placement is rarely permitted; must generally sit behind the primary dwelling
1,200 sq ft or 50% of the primary dwelling's floor area, whichever is smaller
Matches the primary structure
Common approach for above-garage conversions; true basements are uncommon in San Jose's housing stock
Junior ADU (within existing walls)
500 sq ft
Same as primary structure
Must be carved from existing living space; owner-occupancy generally required
Allowed zoning districts
All zoning districts that allow residential use, citywide, including single-family and multifamily zones under San Jose Municipal Code Title 20. Confirm your parcel's zone and eligibility through the city's ADU information tools or SJePlans.
Additional standards
Setbacks, parking & other rules
Setbacks
4 ft minimum from rear and side property lines for detached ADUs (some configurations allow 0 ft on the first floor and 4 ft on the second); front setback generally follows the base zone
Parking
1 off-street space is generally required, but waived if the ADU is within a half-mile of public transit or created by converting an existing garage or carport
Units per lot
1 ADU + 1 JADU on a single-family lot. Multifamily properties have their own allowances, and state law under SB 1211 permits up to 8 detached ADUs on qualifying multifamily lots
Owner-occupancy
Not required for ADUs, permanently eliminated statewide by AB 976 effective January 1, 2024. JADUs generally still require an on-site owner
Building code
Must meet California Residential Code / California Building Code dwelling-unit standards
Short-term rental
Not permitted. San Jose restricts ADU rentals to long-term occupancy; short-term platforms like Airbnb or VRBO are prohibited for ADUs regardless of the host's own short-term rental registration status
Ordinance history
How San Jose's ADU rules got here
2017Statewide ADU law arrives. SB 1069 and AB 2299 take effect January 1, 2017, creating the first modern statewide ADU framework that local ordinances must align with.
2019San Jose updates its zoning code. On December 17, 2019, the City Council votes to align local ADU standards with the new 2019 state law package (AB 68, AB 881, AB 670, SB 13), effective alongside state law on January 1, 2020.
2020Tiny homes on wheels added. The Council approves treating tiny homes on wheels as a form of detached ADU on April 14, 2020, effective May 29, 2020.
2024Owner-occupancy ban made permanent; ADU condos approved. AB 976 takes effect January 1, 2024, permanently barring owner-occupancy requirements statewide. That June 11, the City Council approves an ADU condominium ordinance as part of a broader zoning code update, letting ADUs be sold separately from the primary home. San Jose issued 488 ADU building permits that year, and the city has now doubled its annual ADU permit volume over the past five years.
2025Multifamily ADU capacity expands; first ADU condo sale. SB 1211 takes effect January 1, 2025, allowing up to 8 detached ADUs on qualifying multifamily lots. That August, San Jose is reported to have approved the first ADU condominium sale in California under its new ordinance.
The city reports roughly 1,500 ADUs permitted since 2022 and more than 1,100 final building permits issued, with a growing share of large ADUs: more than a third of recently permitted units now exceed 700 sq ft, a shift from the smaller, cheaper units that dominated the early years of the ordinance.
Permit process
How San Jose ADU permitting works
1
Pre-application eligibility check
Confirm your zoning, lot size, and existing structures before designing.
2
Choose your plan path
Use a pre-approved standard ADU plan set for faster review, or submit a fully custom design.
3
Prepare your plan set
Site plan, floor plans, and elevations, submitted electronically through the city's SJePlans portal.
4
Plan review
Qualifying projects receive ministerial review, with a decision required within 60 days of a complete application under state law.
5
Pay fees & pull permit
Permit fees typically run $1,000-$5,000; school impact fees apply only to ADUs 750 sq ft or larger.
6
Construction & inspections
Build to code and schedule inspections through final sign-off.
Fees and timelines are approximate and vary by project size and complexity - confirm current figures with the Development Services Permit Center.
Budgeting
What it costs to build an ADU in San Jose
Garage conversion
Roughly $85,000-$175,000 (a one-car garage runs toward the lower end, a two-car garage toward the higher end)
Basement conversion
Uncommon in San Jose's housing stock, since most homes here are built slab-on-grade. Where feasible, costs run comparable to a garage conversion - confirm with a local contractor
New detached ADU
Roughly $250,000-$450,000+ (about $350-$500 per sq ft), reflecting Silicon Valley labor and land costs
Permit fees
Roughly $1,000-$5,000 depending on project size and complexity
School impact fees
Waived for ADUs under 750 sq ft; apply above that threshold - contact the local school district for current rates
These are general ranges from local contractor estimates and regional reporting, not quotes - actual cost depends heavily on lot conditions, finishes, and whether utilities need to be extended.
Before you apply
Tips for a smooth approval
Check the transit-proximity map before assuming you need parking. Many San Jose lots near light rail or bus rapid transit qualify for the parking waiver, unlike a typical detached ADU elsewhere in the city.
Keep your ADU under 750 sq ft if you want to skip school impact fees. That threshold makes a meaningful difference in total project cost.
Ask about pre-approved standard plans. They can speed up review considerably compared to a fully custom design.
Plan for long-term rental only. San Jose doesn't allow short-term rental of ADUs, so factor that into your return-on-investment math from the start.
Confirm setback and height specifics for your exact zoning district. Standards can vary by district, so a quick check before you finalize your design avoids costly redesigns.
FAQ
Common questions
Do I need to live on the property to build an ADU in San Jose?
No. California's AB 976 permanently eliminated owner-occupancy requirements for ADUs statewide as of January 1, 2024. JADUs generally still require an on-site owner.
How many ADUs can I build on one lot?
On a single-family lot, 1 ADU plus 1 JADU in addition to the primary dwelling. Multifamily properties have their own allowances, and state law now permits up to 8 detached ADUs on qualifying multifamily lots.
Do I need extra parking for an ADU?
Usually yes: 1 off-street space is generally required, unless your lot is within a half-mile of public transit or the ADU is created by converting an existing garage or carport.
How long does the permit process take?
State law requires a ministerial decision within 60 days of a complete application. Confirm current processing timelines with the Development Services Permit Center.
What's the maximum size for a detached ADU?
1,200 sq ft, with a 16 ft height limit in most zoning districts.
How much does an ADU cost to build in San Jose?
Garage conversions tend to run roughly $85,000-$175,000, and new detached units roughly $250,000-$450,000 or more, based on local contractor estimates and regional reporting - not counting permit or school impact fees.
How many ADUs has San Jose actually permitted?
The city issued 488 ADU building permits in 2024, up from just 10 in 2015. Roughly 1,500 ADUs have been permitted since 2022, with more than 1,100 final building permits issued, and annual volume has doubled over the past five years.
Can I rent my ADU out on Airbnb or a short-term rental platform?
No. San Jose restricts ADUs to long-term rental only; short-term platforms like Airbnb and VRBO are not permitted for ADUs.
