Of all the regulations applicable in the Bay Area, those in San Francisco are by far the most complex, primarily due to the density of housing developments and the age of the buildings. If you are interested in exploring an ADU in San Francisco, you are recommended to read all of the excellent information published by the City, links are provided below.
The City and County of San Francisco has a page for ADUs
San Francisco also published an ADU Handbook Please note that this is not completely up to date because of code changes. It will be updated in the summer of 2018.
Also available is the ADU Video created by San Francisco: “Are ADUs right for you?”
There are two programs for adding ADU(s) to your property in San Francisco:
- Waiver ADUs – this program applies to projects in multi-unit buildings and single-family homes that require waivers from the Planning Code to add the ADU, or 207(c)(4) See Fact Sheet and FAQ
- No Waiver ADUs – this program applies to single-family homes that do not require any waivers from the Planning Code, or 207(c)(6) See Fact Sheet and FAQ
*If you’re looking to legalize an existing unauthorized unit, please review San Francisco Planning’s Fact Sheet on the Legailzation program. More information is also available on the Department of Building Inspection webpage here: http://sfdbi.org/UnitLegalization.
Many cities that have formalized their ADU policies have limited the size of dwelling units that can be considered “accessory” or “secondary” – sometimes as a percentage of the primary dwelling, and sometimes as an absolute maximum square footage. San Francisco currently has only one zoning designation that speci cally regulates secondary units – ADUs in RH-1(S) zones are limited to 600 square feet. In other residential zones, there are no limits placed on the size of new dwelling units.