San Mateo ADU size limits
Min: None Max ADU: No max size limit, dependent on underlying zoning FAR (allowing at least an 800 sq ft) Max JADU: 500 square feet
San Mateo County
San Mateo ADU rules
San Mateo has an official local rule record in this scrape. Provider research is grouped at the San Mateo County level.
Direct answer
Can I build an ADU in San Mateo?
San Mateohas an official local ADU rule record in this directory. Start with the city's size, height, setback, parking, and owner occupancy standards below, then confirm lot-specific limits with the official source before hiring design or construction help.
San Mateo ADU rule guide
San Mateo height and setbacks
Detached ADUs: 16 feet to building plate; 24 feet max Attached ADUs: 24 feet to building plate; 32 feet max *Two story units are allowed provided they meet these standards. Side and rear: 4 feet Front: Set by underlying zoning Separation from main residence (detached): 4 feet Daylight Plane: meet R1 daylight plane from side and rear property line
San Mateo parking and owner occupancy
JADUs: No parking required ADUs: One spot unless ADU meets one of the State law exemptions JADUs: Required ADUs: Not required
How San Mateo ADU permitting works
-at-a-Glance FAQs Floorplans Inspiration Glossary Guidebook + Exercises Pre-Designed Plans Process-at-a-Glance See the resources page Events About Contact Getting Started Learning the Rules Budgeting Design Permitting Construction Renting Getting Started Learning the Rules Budgeting Design Permitting Construction Renting Home » Local Rules » San Mateo City Local ADU Rules San Mateo City...
Local rule facts
Min/max ADU size
Min: None Max ADU: No max size limit, dependent on underlying zoning FAR (allowing at least an 800 sq ft) Max JADU: 500 square feet
Height
Detached ADUs: 16 feet to building plate; 24 feet max Attached ADUs: 24 feet to building plate; 32 feet max *Two story units are allowed provided they meet these standards.
Setbacks
Side and rear: 4 feet Front: Set by underlying zoning Separation from main residence (detached): 4 feet Daylight Plane: meet R1 daylight plane from side and rear property line
Parking
JADUs: No parking required ADUs: One spot unless ADU meets one of the State law exemptions
Owner occupancy
JADUs: Required ADUs: Not required
Process
-at-a-Glance FAQs Floorplans Inspiration Glossary Guidebook + Exercises Pre-Designed Plans Process-at-a-Glance See the resources page Events About Contact Getting Started Learning the Rules Budgeting Design Permitting Construction Renting Getting Started Learning the...