California’s Duplex Law Isn’t Working. Now What?

A new UC Berkeley report shows SB 9 has failed to spur multi-family housing construction across the state. Frustrated with the slow pace of building, housing advocates could pursue additional legislation that wrestles more control away from localities. 

SB 9 allows up to four dwellings (as many as two duplexes or two houses with attached units) to be built on almost any lot currently zoned for a single-family residence. Cities can only veto the development when there is a threat to health and safety. 

The bill was opposed by hundreds of local governments. Proponents argued it would dramatically increase the state’s housing supply, helping to bring down prices.

UC Berkeley’s Terner Center analyzed 13 cities considered to be prime areas for SB 9 projects — Anaheim, Bakersfield, Berkeley, Burbank, Danville, Long Beach, Los Angeles, Sacramento, San Diego, San Francisco, San Jose, Santa Maria and Saratoga. SB 9 projects in these cities were “limited or nonexistent,” the study found. Only 282 applications were made for SB 9 projects and just 53 had been approved. 

By contrast, ADU construction remains incredibly popular. Los Angeles alone issued permits for 25,881 ADUs between 2017 and January 2023.

“To replicate that success, the Terner Center report suggested cutting fees associated with new duplex development, or adding more uniform standards for SB 9 projects to ensure local governments can’t attach subjective criteria that discourage applications, such as architectural design requirements or stringent landscaping rules,” the LA Times’ Hannah Wiley reports. “It also proposed revising a mandate that homeowners who split their lots must live in one of the units for at least three years, a key concession lawmakers made to reduce opposition from organizations worried about gentrification.”  

Matthew Lewis, spokesperson for California YIMBY, also said SB 9 may need to be changed in order to get the results advocates were hoping for. Duplexes require more financing than ADUs and must include a separate sewer line and water service. Along with the three-year occupancy requirement, these are just some of the barriers to building. 

Senate President Pro Tem Toni Atkins (D-San Diego), author of SB 9, wasn’t ready to admit failure just yet. 

“We always said not every homeowner would be able, or want, to utilize the tools provided by the bill on Day One,” Atkins said in a statement. “Subdividing a lot, or even just adding an ADU, is a big investment. This bill was never intended to be a sledgehammer approach — it was meant to increase the housing supply over time, and as awareness of the law increases and more homeowners have the ability to embrace the tools, I’m confident that we will see results.”