Accessory Dwelling Unit Program in Place City-Wide

​With the housing crunch in San Francisco, there has been a push to allow new residential units to be legalized in areas such as basements, storage areas and garages.  After extended political wrangling between Supervisors Peskin and Farrell earlier this year regarding the nature of an expanded program to legalize Accessory Dwelling Units (ADU’s), compromise was reached, and new legislation went into effect on September 4, 2016.

Previous legislation allowed legalization of ADU’s in District 8 (including the Castro and Noe Valley), and then in District 3 (including Chinatown and North Beach), but the program was not available in other Districts.  Under the new legislation, legalization is available City-wide in Zoning Districts permitting residential use, with the exception of RH1-(D) Districts, which are subject to separate State Law requirements.

What is Allowed

ADU’s, also known as in-law units, are defined as new dwelling units constructed entirely within the built envelope of an existing building in areas that allow residential use, or within the existing built envelope of an authorized auxiliary structure on the same lot, as it existed three years prior to application.

In buildings with four or fewer existing units, one ADU may be added.  In buildings with five or more existing units, there is no limit to adding ADUs as long as Planning and Building Code requirements are met.  Requirements for rear yard, parking, open space, and density may be waived by the Zoning Administrator, and exposure requirements may be reduced.

ADU’s requiring minor expansions in the building envelope are permitted where they are under cantilevered or column supported rooms, under decks that are no more than 10 feet in height above grade, or require infill into light wells if not visible from off-site and are against a blank neighboring wall. However, these expansions cannot encroach into the rear yard and do require neighborhood notification under Section 311 or 312, and, therefore, are subject to discretionary review by the Planning Commission.

An ADU is not to be constructed using space from an existing dwelling unit, and ADU’s in Neighborhood Commercial Districts and the Chinatown Community Business or Visitor Retail Districts may not reduce ground floor commercial space.  Moreover, buildings with recent evictions are excluded.  Therefore, individual properties should be evaluated for eligibility before owners dive in to the application process.

Rent Control and Sale

ADU’s added to rent control buildings are subject to rent control pursuant to a Costa Hawkins agreement with the City.  In addition, ADU’s are not eligible for short term rentals such as through Airbnb.

An ADU may be sold where it is added to a building, without an existing rental unit, that was already a condominium three years prior to July 11, 2016, and has had no evictions within the 10 years prior to July 11, 2016.  ADU’s added in buildings undergoing seismic retrofitting maintain eligibility to enter the condo-conversion program if one becomes available in the future.


ADU permits require an intake through the Planning Department and an application fee.  However, they do not require neighborhood notification unless an expansion of the envelope is requested, as discussed above.  Childcare fees and any impact fees for the plan area will apply, and are due when the permit is issued.

With the significant increase in scope of the ADU program, the City has received numerous applications, and is likely to receive many more this fall and winter.   The City anticipates that processing will take four to six months, but delays in processing should be anticipated (additional applications such as neighborhood notifications, variances and conditional use permits will add more processing time).  If adding an ADU to a historic building presents challenges for your project, having a pre-application meeting with DBI can help you work through Code-compliant solutions prior to submittal.

The issues discussed in this update are not intended to be legal advice and no attorney-client relationship is established with the recipient.  Readers should consult with legal counsel before relying on any of the information contained herein.  Reuben, Junius & Rose, LLP is a full service real estate law firm.  We specialize in land use, development and entitlement law. We also provide a wide range of transactional services, including leasing, acquisitions and sales, formation of limited liability companies and other entities, lending/workout assistance, subdivision and condominium work.