Millbrae Accessory Dwelling Unit (ADU) Standards

INFORMATION  
Contact

Planning Division – 650-259-2341

Website
ADU Ordinance

Millbrae does not have an ordinance governing ADUs, so state law applies.

STANDARDS  

Zones allowed

All residential zones with an existing single-family residence
Lot restrictions

None

Minimum lot size

None

Min / Max ADU size

150 sf / 1,200 sf or 50% of the main dwelling, whichever is less

ADU building height

No restrictions

Setbacks

Must have sufficient setbacks for fire safety

Parking requirements

No parking is required

Owner occupancy

No requirement

Fees

The exact amount of fees varies depending on the specifics of the proposal. In addition, there are various services provided by other districts, such as fire, sanitary, water, and schools that may assess a fee.

Other requirements
  • ADU must provide direct outside access.
  • ADU must have sufficient setbacks for fire safety.
  • ADU may not be sold separately from primary residence.
  • ADUs must comply with all requirements of the underlying zoning district.
Process

Building permit review required. Making an appointment to meet with a planner in the initial stages of the project can help avoid challenges and is highly recommended.

Exceptions

None

Disclaimer: standards and process may vary. Consultation with the contact is recommended before starting any project.

Download ADU Standards PDF

Updated: 12/11/2017