Accessory Dwelling Unit Program per Ordinance 162-16

Announcement: New Submission Process for Accessory Dwelling Unit Applications

Starting November 2, permit applications for Accessory Dwelling Unit (ADU) or related ADU construction work can be submitted using an online form through the City's website here. Your application will be processed by SF Planning using the Electronic Plan Review process. If you submitted an ADU request to DBI after August 17, you will be contacted by SF Planning staff with more information.

Accessory Dwelling Unit Program available Citywide

Picture of house on top of construction plans

As of September 2016, Ordinance No.  162-16 allows the construction of accessory dwelling units (ADU) Citywide in areas that allow residential use. This program reduces some Planning Code requirements to make it possible for property owners to add ADUs.





Department of Building Inspection
Accessory Dwelling Unit Program
49 South Van Ness Avenue, 2nd Floor
San Francisco CA 94103
(628) 652-3705

Planning Information Counter
49 South Van Ness Avenue, 2nd Floor

San Francisco CA 94103




Accessory Dwelling Units, or ADUs, are units added to existing residential buildings. They’re also known as secondary units, in-law units, cottages, or granny flats. Nationwide, cities have been adopting ADU programs into their local laws to allow underutilized areas such as parking, yards, storage, or boiler room space to be converted to new homes. San Francisco first adopted its Accessory Dwelling Unit Program in 2014 for select districts.

In September 2016, the City of San Francisco's Accessory Dwelling Unit Program became available for use citywide. This program reduces some Planning Code requirements to make it possible for property owners to add these new units to their buildings.

In June 2017, amendments were made to the Planning Code to bring the requirements and procedures for authorizing the construction of Accessory Dwelling Units in single-family homes into conformity with the new mandates of State law. (Ordinance No. 95-17)

Further amendments were made in August 2017 (Ordinance No. 162-17) which have introduced additional flexibility to the program. 


Existing Units Number of New ADUs Allowed
4 or less per lot 1 ADU Allowed
5 or more per lot No Limit*

If a building on the lot is undergoing mandatory or voluntary seismic retrofit (AB 094), there is no limit to the number of ADUs that can be added to the lot.

*As long as it fits within building envelope and meets Planning and Building Code requirements.


Buildings undergoing mandatory seismic retrofit per SFBC Ch 34B (SFEBC Ch 4D) or voluntary seismic retrofit per AB-094, may raise building up to 3 feet to create ground-floor ceiling height and shall maintain eligibility for subdivision or condo conversion.

Note: Seismic retrofit and ADU must be separate permits and separate sets of plans.


  1. An application may not be filed to add an ADU to a building that has had an owner move-in eviction in the last five years or other no-fault evictions in the last 10 years. With exception are temporary tenant evictions for capital improvements. 
  2. ADUs must be constructed within the existing building envelope. Expansions are permitted in limited circumstances.
  3. ADUs can take space from an existing residential unit in limited amounts. Up to 25% of ground floor or basement level habitable space may be converted to an ADU.
  4. ADUs cannot be merged with an original unit(s).
  5. ADUs may not be permitted in a Neighbor Commercial District or in the Chinatown Community Business or Visitor Retail Districts if it eliminates or reduces a ground-story commercial space.
  6. ADUs may not be used for short-term residential rental.
  7. ADUs cannot pursue subdivision or condo conversion, except buildings that were a condominium building for 3 years prior to July 11, 2016, or undergoing seismic retrofit.
  8. If the existing building is rent controlled, and Planning Code waivers are granted, the new unit will also be subject to the Rent Ordinance, including rent controlled.
  9. 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.

ADU applications that meet the following criteria and do not require Planning Code waivers may be eligible for review and approval by Planning in 120 days or less, if no expansion is proposed:

  1. Adding one ADU to a single-family home.
  2. No parking is required for the ADU.
  3. The ADU can be created from the existing dwelling unit, from within the buildable area of the lot, or can be created from an existing and authorized auxiliary structure on the lot.
  4. The project is not undergoing the mandatory seismic retrofit per SFBC Ch 34B (SFEBC Ch 4D) or voluntary seismic retrofit per AB-094.
  5. Expansion is permitted within the buildable area of the lot to add the ADU.