ADU Builder in San Bruno, CA
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San Bruno ADU Rules
San Bruno amended its ADU chapter (12.90) in 2025. ADUs are approved ministerially within 60 days, with one ADU plus one JADU on a single-family lot.
- JADU up to 500 sq ft.
- ADU up to 850 sq ft (studio or one bedroom) or 1,000 sq ft (two or more) on lots under 7,500 sq ft, and 1,200 sq ft on larger lots; 800 sq ft always allowed.
- 4-foot side and rear setbacks; detached 16 to 18 feet, or up to 25 feet over a garage.
- No sprinklers unless the main house requires them; no rentals under 30 days.
- Separate gas and electric meters for each unit.
San Bruno also has a pre-approved ADU plan program.
ADU Construction
Permits
Heritage trees: native bay, buckeye, oak, redwood or Monterey pine of 6 inches or more in diameter, and any other tree of 10 inches or more, need a separate permit from Community Services, (650) 616-7196, with an arborist report.
567 El Camino Real, San Bruno, CA 94066 · (650) 616-7074 (option 2 Building, option 3 Planning)
Open Monday to Thursday, 7:30 a.m. to 5 p.m.; City Hall is closed Friday to Sunday, and Planning asks visitors to book an appointment. Permits run through SB Permits (MGO Connect): request inspections there with an AM or PM window by 3 p.m. the day before.
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Other San Bruno services: Bathrooms · Kitchens · Additions · New Homes · San Bruno overview
Same service nearby: Millbrae · Burlingame · San Mateo
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San Bruno ADU Builder FAQ
How big can an ADU be in San Bruno?
850 or 1,000 sq ft on lots under 7,500 sq ft, and 1,200 sq ft on larger lots.
How long does approval take?
Ministerial review within 60 days.
Are separate meters required?
Yes, separate gas and electric meters for each unit.
Does San Bruno have pre-approved ADU plans?
Yes.