Accessory Dwelling Units Authorized in New Construction

June 20, 2019

New legislation passed by the San Francisco Board of Supervisors on June 18 now authorizes the addition of Accessory Dwelling Units (ADUs) in new construction projects for single-family homes and multi-family buildings.

The City offers two ways to build an ADU. Under the Local ADU program, also referred to as the “Waiver” program, the creation of an ADU would need one or more waivers from the Planning Code for requirements such as exposure, open space, or rear yards. Under the “No-Waiver” program, which is the City’s State Mandated ADU program, one ADU is permitted within existing single-family homes that strictly meet the state law’s ADU requirements without requiring waivers from Planning Code requirements.

Under the newly passed legislation, ADUs would be permitted in new construction of single-family or multi-family buildings under the local “Waiver” program. The number of new ADUs authorized would be based on the size of either the existing building or what the zoning would permit for new construction.

Buildings with four or fewer units may construct one ADU. For buildings with four or more units, there will be no limits on the number of ADUs permitted, subject to the buildable area of the lot, and so long as there was no tenant who was served an eviction notice on that site within 10 years prior to filing the application for a building permit to construct an ADU. Where permitted by the Planning Code and/or state law, project sponsors may seek waivers from Planning Code requirements that set limits on the physical nature of the project, such as rear yard, open space, and height requirements. Coupled with the newly adopted legislation, ADU projects under the “Waiver” program are no longer restricted by density controls in the base zoning.

Buildings undergoing mandatory seismic retrofit work also will not be capped in the number of ADUs that may be added. Buildings undergoing voluntary seismic retrofit work are eligible to add more than one ADU. The local program still requires neighborhood notification and allows for the opportunity for Discretionary Review by the Planning Commission.

To conform with state law, the legislation requires that ADUs under the “No-Waiver” program be approved ministerially. The ADU can be located within the existing building, in addition to the existing building, or in a new construction building. When the ADU involves expansion of the built envelope of an existing primary dwelling, or an expansion of the built envelope of an existing and authorized stand-alone garage, storage structure, or other auxiliary structure on the same lot, or the construction of a new detached auxiliary structure on the same lot, the total floor area of the ADU cannot exceed 1,200 square feet under the new legislation. The “No-Waiver” program does not require neighborhood notification, nor provide the opportunity for Discretionary Review, as per state law.

There is a pending amendment to the “No-Waiver” program which would require that the total area of floorspace of an ADU within new construction of a single-family dwelling be not less than 50 percent of the proposed primary dwelling living area, unless it is an efficiency unit (as defined in Section 1208.4 of the San Francisco Building Code).

The newly adopted legislation is available here. The duplicated file with the pending amendment is available here. For additional resources on ADUs, visit the Planning Department’s website here.

(under newly adopted legislation)

Local ADU Program (Planning Code Sec. 207(c)(4) – “Waiver” Program State Mandated ADU Program (Planning Code Sec. 207(c)(6) – “No-Waiver” Program
ADUs allowed in new construction of single-family dwelling or multi-unit building. One ADU allowed in either existing or new construction of single-family dwelling.
Buildings with 4 units or less: One ADU authorized. Ministerial approval process – no Discretionary Review.
Buildings with 4 units or more, or undergoing mandatory seismic retrofit: No limit on ADUs (subject to tenant eviction history within 10 years of filing building permit and other Planning Code requirements, which may be waived). If ADU involves expansion of built envelope of existing building or standalone garage/structure, total floor area of ADU cannot exceed 1,200 square feet.
Subject to Discretionary Review. No neighborhood notification.
Neighborhood notification required. Pending amendment: Total area of floorspace of ADU within new construction of single-family dwelling cannot be less than 50 percent of proposed primary dwelling living area (unless it is an efficiency unit). 

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