San Mateo ADU Laws & Regulations

Zoning

R-1/R-2/R-E/RH/RM/TPZ (within the Coastal Zone, only R-1 is permitted)

Lot Size

Exempt from minimum lot and density provisions of underlying zoning district.

Maximum ADU Floor area

1200sf

Rear Yard Coverage

Must adhere to requirements of underlying zoning district.

No. Bedrooms

NA

Kitchen

Full kitchen facility required (permanent range, counter, refrigerator, sink)

Bath

Required

Parking

No, if the ADU meets exemptions from parking requirements 

Setbacks

Front

Side

Rear

 

Established by Zoning District

4ft

4ft

Height

16ft

Design

Be constructed of the similar exterior materials, finishes, and family of colors as the primary residential dwelling unit

Entryways

Required

Second Address

Required, consult Building Department

ADU Regulation Website

https://planning.smcgov.org/sites/planning.smcgov.org/files/SMCo_Coastal_Zone_ADU_Regulations_Zoning_Chapter_22-5-1.pdf