As California’s housing crisis and political divisions deepen, its lawmakers are trying every legislative trick in the book to get any relief to stick.

Senate Bill 9 (SB 9) is the latest of these efforts. The bill is only part of the California Senate’s Building Opportunities for All housing package, a multi-faceted approach to combat the state’s housing woes.

More specifically, SB 9 aims to ease the process and ability of homeowners to create a duplex or subdivide their single-family residential lot into up to four units. Proponents tout the bill’s potential to increase affordable housing stock in a tight real estate market and open up additional income sources for homeowners.

SB 9 was approved by the California Assembly on August 26, 2021, in a 44-16 vote, then approved by the Senate on August 30 in a 28-7 vote. Opponents of the bill hoped the recall of Governor Newsom would make the bill null and void, but in the wake of Newsom’s win, that strategy has met a dead end. Newsom officially signed SB 9 into law on September 16, 2021.

Now that SB 9 has been signed into law, how its effectiveness and reception unfolds in the long term remains to be seen.


Yes-in-my-backyard (YIMBY) activists view this law as a progressive step in the right direction, modernizing communities and making homeownership more accessible and affordable. They argue bans on duplexes perpetuate the legacy of redlining by making it more difficult for people of color to afford to live in high-opportunity neighborhoods.

High-opportunity neighborhoods are those classified as providing access to community attributes and amenities often indicative of increased economic mobility. These attributes and amenities include higher job density, higher income, lower poverty and unemployment rates, increased completion of higher education and are predominantly white in population.

In contrast, lower-opportunity neighborhoods are characterized by lower job density, lower income, higher poverty and unemployment rates, decreased completion of higher education and are predominantly populated by people of color. While these are not hard and fast rules, the pattern — and its discriminatory outcome — is hard to ignore.

Not-in-my-backyard (NIMBY) activists fear the bill threatens single-family zoning and subsequently homeownership in California. They claim that this one-size-fits-all statewide attempt at a housing solution is short sighted and usurps local control. Additionally, the risk of increased housing density may negatively affect property values. This is naturally concerning to them as homes are often people’s biggest financial asset.

However, SB 9 stipulates any new housing created under it must meet a specific list of qualifications that protect environmental quality, historic districts and existing tenants vulnerable to displacement. Additionally, it has been amended to require a three-year owner occupancy for lot splits.

Perhaps the most damning argument against SB 9 lies in how it will be enacted. The bill does not set a price cap for these new units, nor does it set out affordability requirements. Detractors point to this as evidence that SB 9 would bring the greatest benefit to the wealthiest homeowners and developers.

NIMBYs are correct that the law has no built-in affordability clause or amendment. YIMBYs assert the size and classifications of the units themselves with market rate will automatically be affordable. Still, there’s nothing to stop wealthy developers that only see dollar signs.

The political history of single-family zoning

Single-family zoning has long been painted as integral asset and part of the homeownership landscape that “preserves character.” Yet it has racist beginnings.

In 1916 Berkeley, California, single-family zoning was enacted to block a Black-owned dance hall from moving into a predominantly white neighborhood. This also precluded multi-family units, more commonly occupied by people of color, from being built.

Some argue as there’s no way to extricate this exclusionary zoning from its racist history and the echoes it carries in neighborhoods today as a symbol of segregation and racism, it should be done away with by default.

But the reality of California’s housing and political landscape rules out such a sudden and sweeping measure, despite its pro-housing intentions. Meaningful change often comes at a frustratingly slow pace, and California’s long-simmering housing catastrophe is no exception. Accordingly, lawmakers considerably focused SB 9’s scope compared to previous high-profile housing legislation like SB 50.

SB 9’s impact

Proponents of the law insist it is likely to result in “modest,” “light” or “gradual” density. Research by University of California Berkeley’s Terner Center for Housing Innovation confirms this claim of gradual density is accurate, stating development would only be realistic to 5.4% of land owned and occupied by single-family homes or 410,000 parcels in California at most.

Assuming every single homeowner with the potential to develop did, that would total to about 700,000 new units across California. The three-year owner occupancy amendment would cut this potential total unit number to 660,000 units. However, this number of units may not be realized because the average homeowner cannot afford to build a second unit, much less a third or fourth.

California is not the first state to ban single-family zoning. Minneapolis City Council elected to eliminate single-family zoning in 2018 and Oregon became the first state to ban single-family zoning in many of its cities in 2019. The single-family zoning ban in Minneapolis is still in its infancy, so long-term results are not yet known.

A 2019 Terner Center study suggests the single-family zoning ban in Minneapolis has displayed an increase in the price of some single-family homes. Even so, this rise proved essential to encouraging redevelopment resulting in affordable housing options.

For agents, SB 9 and California’s Building Opportunities for All package remains a double-edged sword. A transition away from single-family zoning complicates the suburban dream to which Californians have long aspired.

At the same time, shrewd agents understand that sales volume is the bottom line. Opening up California’s long-stagnant suburbs also represents more transaction fees. After all, there are only so many million-dollar transactions to go around.

Agents — keep up to date with your local governments to see how they choose to implement this policy going forward. How California’s cities embrace this new law will dictate how real estate professionals survive the recession hangover.