Compare cities · Santa Clara County
The most generous city on paper: ADU building-permit, plan-check and MEP fees are all $0 in the FY2026-27 schedule, and the city gives away nine permit-ready detached plan sets. The trade-offs are a 16 ft one-storey cap on detached units in the code, a daylight plane, and a recorded deed restriction on every ADU.
Nine free city permit-ready detached plan sets (three styles, 525 / 854 / 1,190 sq ft) with full structural and MEP drawings, plus private pre-approved plans. Under state law a detached unit built from a pre-approved plan gets a 30-day decision instead of 60.
Program page →FY2026-27 fee schedule (effective 1 July 2026): ADU building permit, plan check, and electrical, mechanical and plumbing permits all $0. Construction tax and outside-agency fees still apply.
Nine detached plan sets in three styles and three sizes, including structural, mechanical, electrical and plumbing drawings.
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.
Los Altos 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 Los Altos, 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.