Many single- and multi-family homes in San Francisco can now add units. You can use the space for family members or to rent for extra income.
This process may take more than 18 months from when you decide to build.
It typically costs more than $125,000 in materials and labor to add a unit. Professional services for architects and engineers are about 10% of construction costs. City fees range from 6 to 9% of construction costs. Your total cost can range widely depending on the specifics of your location and project.
Find ADU grants available through the California Housing Finance Agency.
Your property and project plans affect what processes you must follow to get a building permit. Projects may be longer if they include multiple ADUs, seismic work, variances, or a Certificate of Appropriateness.
Prepare for an ADU project
Decide if an ADU is right for you. Check our rules and hire a professional to design your ADU.
Check rules for adding an ADU with the Local program
If you are using the Local ADU program and your building has tenants, you must follow additional rules, including posting a notice.
Check rules for adding an ADU to a building with the Local program
Apply to build an accessory dwelling unit (ADU)
Follow these steps to apply for your permit online.
Application review and first permit fee
After you apply, we review your application materials.
We may ask you for more information or corrections to your application.
Plan review
We will review your plans.
Accessory dwelling units (ADU) must meet City requirements that keep buildings safe and neighborhoods livable.
Most ADU plans must be reviewed by multiple City agencies like SF Planning, SF Fire, SF Department of Building Inspection (including Building, Mechanical, and Structural), SF Public Works, and SF Public Utilities Commission. We will route your application to each required plan check.
Permit issuance
Your permit application will go through a comprehensive review process.
All City departments have to approve your permit before we can issue your permit.
After we have reviewed your application, we will tell you:
- What your final fee is
- How to pay your final fee
- What next steps to take (if any)
Start construction
If you have a full permit, you can start construction once you receive your construction document.
If you submitted a site permit, you will need to submit your addendum. We will email you instructions to submit your addendum online. You can start construction once your addendum is issued.
Full and site applicants may need additional permits.
Learn what you need to start construction on your ADU.
Last updated December 13, 2023