Today, the San Francisco Board of Supervisors passed an ordinance that will allow for all new single-family homes to be developed as duplexes, by including an accessory dwelling unit (ADU). Further, the ordinance would exempt ADUs added to existing single-family homes from the city’s cumbersome discretionary review process. These changes bring the San Francisco rules up to the state standards after years of non-compliance. It also represents the end of single-family zoning in much of the city, although further changes would be needed to make ADUs a practical option on many properties.

Almost a year ago, the San Francisco Board of Supervisors updated the city’s regulations for ADUs. These local regulations are required to live up to state minimum standards intended to encourage ADU development on single-family properties. Last summer’s changes to the city regulations contained two clear conflicts with the state law standards: the ordinance prohibited ADUs in new single-family homes, and allowed neighbors to contest ADU applications through the city’s discretionary review process. The Planning Commission and the Board still passed the ordinance with these two conflicts despite our comments at multiple public hearings pointing out the issues.

We filed our lawsuit early this year, but put it on hold to see if the San Francisco could fix the problem through its own legislative process. Today, thanks to our lawsuit, and the efforts of YIMBY Action, Supervisor Safai, and Mayor Breed, the Board has finally voted to bring their regulations into compliance with the requirements of state law.

This is a good start. As a practical matter, there are still more changes needed before San Francisco can see widespread development of ADUs. Zoning requirements designed to accommodate only one single-family home on a lot—such as rear yard setbacks and open space requirements—still prohibit ADUs on the majority of lots. San Francisco has been a leader in allowing for ADUs in multi-family buildings, but true to form it has lagged behind in allowing for any development in its single-family neighborhoods. We are happy that San Francisco has taken these two important steps toward encouraging ADU development in single-family neighborhoods.