San Francisco ADU Guide (Updated)
A Comprehensive Guide to ADU Regulation and Zoning Policy in San Francisco, CA
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Accessory dwelling units are typically more difficult in San Francisco, but recent State regulations have eased some requirements for permitting an ADU. However, although there are fewer restrictions, the City of San Francisco Planning Department still requires far more than most of its surrounding city counterparts — largely due to city density and a resulting list of building requirements that will help keep its citizens safe.
Nonetheless, due to the rapidly increasing cost of owning and renting in San Francisco, many homeowners and property owners are still turning to ADUs to create additional infill housing in an already dense city that continues to grow with workers every year. These new units create an opportunity to provide modern accommodations for long-term renters, family, and friends.
Although it can be difficult to navigate San Francisco’s ADU program, the planning department is welcoming of the ADU as an innovative housing solution to address homelessness and commuting congestion due to lack of affordable in-city housing. The key to receiving a stamped permit from the building department is an organized project plan that meets all planning and building requirements and provides safe accommodations for residents or prospective residents of the city.
If you’re building in San Francisco and can’t find the information you’re looking for in our permitting guide, you can visit San Francisco’s ADU support pages here:
General Qualifications: https://sfplanning.org/accessory-dwelling-units
Planning Booklet: https://sfplanning.org/sites/default/files/documents/current/Waiver_ADUFactSheet.pdf
General Notes on San Francisco ADU Regulation
City of San Francisco is currently updating it’s local planning requirements to reflect adjustments with compliance with the State ADU Mandate on January 2020
Recent 2019 updates to the California Building Code and California Residential Code are in effect
San Francisco has 2 classifications of ADU
“Waiver” ADUs – The Local ADU Program allows adding ADUs to existing or proposed single- and multi-family buildings (subject to relevant requirements and Codes)
“No-Waiver” ADUs – The State ADU Program allows the addition of ADUs, detached ADUs, or Junior ADUs to existing or proposed single-family buildings; and the addition of ADUs or detached ADUs to existing multifamily buildings. State law does not allow the addition of ADUs to new construction of multi-family properties.
Bay Modular’s pre-approved Solo ADU Series is designed to meet the State ADU Mandate and is 100% compliant with the 2019 CBC/CRC
All Solo ADUs are pre-approved by the State of California Department of Housing and Community Development (HCD #1560585) and do not require any additional local plan check, inspection, or approval
All site preparation, foundation work, and utility upgrade & connection related to the installation of all Solo ADUs will still require local plan check, and inspection
Due to statewide updates to ADU regulations, it has never been easier or more affordable to build a permitted ADU
City of San Francisco: Planning Department Contact Information
Phone Number: (415) 558-6377
Email Address: CPC.ADU@sfgov.org
General Resource: https://sf.gov/contact-city-about-your-adu
Citywide ADU Program Resource: https://sfdbi.org/adu
ADU Application: Download PDF
Location:
SF Planning Department, ADU Counter
1660 Mission Street
1st Floor
San Francisco, CA 94103
Detailed San Francisco ADU Regulations & Guidelines
ADU Size Restrictions (Updated January 2020)
For existing or new single-family properties, any two of the options below can be combined, for a total of three units per lot, including the single-family home:
Attached or converted ADU is allowed up to 800 SF (1 bedroom) or 1,000 SF (2 bedroom)
Detached ADU is allowed up to 800 SF (1 bedroom) or 1,000 SF (2 bedroom)
A junior ADU is allowed up to 500 SF of existing space in the primary residence
For existing multi-family properties:
One attached or converted ADU is allowed up to 800 SF (1 bedroom) or 1,000 SF (2 bedroom). In some cases, more than one is allowed, up to 25% of the # of existing units (e.g. if existing property contains 16 units, 4 ADUs are allowed).
Two detached ADUs are allowed up to 800 SF (1 bedroom) or 1,000 SF (2 bedroom).
The minimum size of any living unit is 150 SF
Lot Size Restrictions (Updated January 2020)
Both single family and multi-family lots will not be subject to the minimum lot size of the underlying zoning district or by ordinance for ADU projects, per AB68
A certain amount of open space is required on each residential lot. Generally 25 to 45% of the property must remain open, depending on how the property is zoned.
Type of ADUs Allowed
Detached ADU, attached ADU, junior ADU are all approved (Solo ADU Series are detached ADUs)
ADUs may be new construction or conversion of existing space (e.g. garage)
Junior ADUs must be conversion of existing space (e.g. garage)
California Building Code (CBC) & California Residential Code (CRC) 2019 is in effect
Number of ADUs Allowed (Updated January 2020)
Single family properties are allowed any two of the following options to be combined with the primary residence: attached/converted ADU, detached ADU, or junior ADU
Multi-family properties are allowed two detached ADUs or a number of ADUs equivalent to up to 25% of existing units (e.g. a building wiht 16 existing units may allow 4 ADUs)
Zoning Requirements (Updated January 2020)
As of September 2016, Ordinance No. 162-16 allows construction of accessory dwelling units (ADU) Citywide in areas that allow residential use. With this program it reduces some Planning Code requirements to make it possible for property owners to add ADUs.
Setback Requirements (Updated January 2020)
The maximum required setback for a detached new construction ADU shall be no more than 4 feet from the rear and side property lines, 6 feet from the primary dwelling
Front setback is often determined by averaging the existing setbacks of the adjacent buildings
Setbacks will not be required for ADUs and junior ADUs that have been converted from existing space that was legally established
Proposed expansions of attached ADUs and conversions from existing space are required to comply with the setbacks of the underlying zone, per AB68
Parking Requirements (Updated January 2020)
ADUs can receive waivers from certain Planning Code regulations such as rear yard, parking, open space, density, and partial exposure (reduction of open area to 15’ by 15’) from the Zoning Administrator.
Properties which convert an existing garage to an Accessory Dwelling Unit or JADU will not be subject to replacement parking requirements.
Fire Safety Requirements
Fire sprinklers are required in all new residential units.
If you’re adding an ADU within an existing home, you may need to add fire sprinklers to the parts of the main home that connect with the ADU and to any escape routes.
Smoke and CO Detectors Smoke alarms are required to be installed in all new dwelling units. These items must be hard-wired into the building’s electrical system.
Architectural Requirements
Exterior modifications will be required to resemble those of the primary structure.
Interior conversions of existing space are not subject to this requirement.
Height Requirements
Single-family properties: 16 feet.
Multi-family properties: 16 feet.
Rescue Window
Rescue openings must be provided from every sleeping room in a dwelling - this means each bedroom needs to have its own rescue opening. Reference 2013 SFBC/CBC Section 1029.
Ownership (Updated January 2020)
Through 2025, owner occupancy requirements will not apply to new ADUs, per SB13. Owner may rent out both the ADU and primary residence.
Rental Restrictions
ADU may not be rented for a period of less than 30 days.
Historic Resource Determination
Buildings 50 years old and older may need to be evaluated to determine whether your planned modifications will damage an historic resource.
Utility Connections
A new or separate utility connection may be required, but the connection fee or capacity charge shall be proportionate to the burden of ADU on the water or sewer system.