Compare cities · Santa Clara County
Cupertino rewrote its ADU chapter in September 2025 after HCD rejected the 2024 version, so the rules are cleaner than most neighbours: up to three ADUs on a single-family lot in any mix, and an 800 sq ft unit gets 18 ft of height and ignores FAR, coverage and open-space limits. Past 800 sq ft, the 45% FAR and the usual rules return.
Six plans from four vendors, 476 to 991 sq ft, detached only, valley-floor parcels without geologic hazards. Standard fees apply. Under state law a detached unit built from a pre-approved plan gets a 30-day decision instead of 60.
Program page →No park, storm drain or school impact fees under 750 sq ft; proportional above (CMC 19.112.020(C)).
Codified AB 2533 path: a permit to legalise a pre-2020 unit may not be denied for code non-compliance unless a substandard-building correction is needed. No fee waiver stated.
State law sets a floor no ordinance can go under. The full guide, with every statute cited →
Every lot zoned for residential use may have at least one ADU, and a single-family lot may also add a JADU. A city cannot say no to the category.
A detached or attached unit of up to 800 sq ft, 16 ft tall, with 4 ft side and rear setbacks must be approved regardless of local lot-coverage or floor-area limits.
A city cannot require more than four feet from side and rear lot lines for an ADU.
Once your application is complete the city has 60 days to approve or deny; 30 if you build from a pre-approved plan.
Convert or demolish a garage to build an ADU and the spaces you lose never have to be replaced.
Prohibited entirely below 750 square feet, and proportional above it.
Reviewed against an objective checklist. No design review board, no hearing, no discretion about whether they like it.
A city cannot require you to live on the property for a standard ADU. A JADU is different: since 1 January 2026 owner occupancy is required when the JADU shares sanitation with the main house.
Cupertino is inside our service area, and ADUs are all we do. We bring in the architect and engineer or work with yours, run the permit with Cupertino, and build with our own crew: about 6 weeks of construction for a detached unit once the permit is in hand.
What we can't tell you from here is what your particular lot will take: setbacks, the sewer lateral, the panel, grade and access. That is what the free site walk is for.
Tell us about your lot and what you're hoping to build. We'll reach out to set a time to walk it with you. No obligation.
Thanks. We've got your details and sent a confirmation to …. Sam or Brad will reach out shortly to set a time for the walk.