ADU Builder in San Carlos, CA
Get a Free San Carlos ADU Consultation
San Carlos ADUs
ADUs and JADUs in San Carlos are approved ministerially, with no hearing. JADUs are up to 500 sq ft, a statewide-exemption ADU of up to 800 sq ft with 4-foot side and rear setbacks is always allowed, there is no owner-occupancy requirement for ADUs, and rentals must be 30 days or longer. Units under 750 sq ft are exempt from impact fees, and pre-approved plans are available.
San Carlos is updating its ADU ordinance after state review in 2026, so we confirm current height and size limits for your lot before design.
ADU Construction
ADU Permits
Sewer lateral: San Carlos requires a CCTV inspection, and repair if needed, of the private sewer lateral with permits that add toilets, create a new connection or cover more than 25% of the building. Occupancy is held until the lateral passes.
600 Elm Street, San Carlos, CA 94070
Building (650) 802-4261, bu******@*************os.org · Planning (650) 802-4263, pl******@*************os.org (first floor; counter Monday to Thursday, 9 a.m. to noon by appointment, closed Fridays)
Submittals are digital only through the City’s Tyler EP&L Customer Self-Service portal. Building counter hours and inspection scheduling are by appointment, so call ahead. Construction hours: 8 a.m. to 5 p.m. weekdays and 9 a.m. to 5 p.m. Saturdays; no work Sundays or holidays.
Explore More
Other San Carlos services: Bathrooms · Kitchens · Additions · New Homes · San Carlos overview
Same service nearby: Belmont · Redwood City · Menlo Park
See how to build an ADU.
San Carlos ADU Builder FAQ
Is there a hearing for an ADU in San Carlos?
No. ADUs and JADUs are approved ministerially.
What size ADU is always allowed?
An 800 sq ft ADU with 4-foot side and rear setbacks.
Do I need to live on the property?
No owner-occupancy requirement for ADUs; JADUs need a recorded deed restriction.
Is the ordinance changing?
Yes. San Carlos is updating it in 2026, so we confirm current rules for each project.