New state law SB9 could shape Berkeley’s effort to end single-family zoning

Nearly 14,000 properties in Berkeley could add new housing under the law, but experts say its impact will likely be modest.

Credit: Pete Rosos

When Gov. Gavin Newsom signed into law a bill allowing property owners to add new housing units to parcels long zoned only for single-family homes, he brought to cities across California a discussion about changes in low-density neighborhoods that got underway in Berkeley earlier this year.

Local planners are now working to figure out precisely how the new state law, known as SB9, will influence Berkeley’s effort to rewrite its zoning codes. But while SB9 was the most controversial piece of housing legislation to come out of Sacramento this year, and nearly 14,000 properties in Berkeley alone could be eligible to build additional units under the law, city officials and experts who have analyzed the legislation say it will likely have only a modest impact on new development.

“There is a tendency right now to either claim that (SB9) is going to be the miracle cure or it’s going to destroy everything — and it’s neither,” said Berkeley Councilmember Lori Droste. “It is one tool within our tool belt to address the housing affordability crisis.”

SB9, which Newsom signed days after surviving the Sept. 14 recall election, allows property owners to split their parcel into two lots and build two units of housing on each lot, allowing in many cases for up to four units of housing in areas where only one could be built before.


In broad strokes, it’s a similar concept to what Berkeley’s City Council approved in March. That resolution, which Droste co-authored, called for changes allowing for the creation of multi-unit “equitable neighborhood scale housing” on parcels now zoned R1 or R1A. The council’s mostly symbolic vote, which drew national attention because Berkeley was the first city in the country to enact single-family restrictions in 1916 as a means of racist exclusion, launched a lengthy public process to change the zoning code and put those concepts into practice.

David Garcia, policy director for UC Berkeley’s Terner Center for Housing Innovation, said the new state law “creates a baseline” for allowing new multi-unit housing on single-family parcels throughout California.

And, Garcia said, it gives cities that want to allow for more dense development the option to “be a little more generous” with their own rules — something Berkeley appears likely to do. The guidance the City Council passed earlier this year is more permissive than SB9: While the state law only goes as far as allowing for two duplexes on a split parcel, Berkeley’s resolution calls for enabling the construction of two-, three- or four-unit buildings, as well as “other building forms that are similar in scale” to surrounding homes.

“In some areas, I think SB9 will be sufficient,” Droste said. “We need to determine areas where it is a floor, and where we might want to allow fourplexes, bungalow courts and what-not.”

Staff in Berkeley’s Department of Planning and Development say they’re still seeking clarification on how to implement SB9, and what kind of impact it could have on the city’s effort to rewrite its zoning code.

“It’s kind of where we were headed anyway with ending exclusionary zoning,” said Grace Wu, a senior planner in Berkeley’s Department of Planning and Development. “But the specifics, and the details, we have to work out.”

For all of the debate SB9 and Berkeley’s resolution have prompted, it also remains unclear just how many new homes those efforts to slightly increase the density of single-family neighborhoods will create as California seeks solutions to its housing crisis.

A Terner Center analysis of SB9 that Garcia co-authored estimated that 13,800 properties in Berkeley would become eligible for new development under the law, out of 17,700 single-family parcels in the city. The law has a number of exemptions — parcels must be at least 2,400 square feet to be eligible for a lot split, and the rules don’t apply in historic districts or areas with high fire risk. Among several provisions meant to prevent displacement, lot-split projects cannot alter or destroy units that have been occupied by a tenant within the last three years or are designated as affordable housing.

From those eligible parcels, the Terner Center estimated that it would be economically feasible to build about 1,100 additional units of housing in Berkeley that would have been prohibited before SB9. That would be a considerable chunk of the nearly 9,000 new housing units the city must plan to add between 2023 and 2031 — but Garcia noted there is no guarantee that an economically feasible project will actually get built, and the number of units ultimately created will likely be much lower.

“We just looked at what pencils” out, he said. “That’s a major project, and a lot of homeowners are not necessarily going to be motivated to do that, even if it is financially advantageous.”

Nico Savidge is Berkeleyside's senior reporter covering city hall. Email: nico@berkeleyside.org. Twitter: NSavidge.