The vast majority of land set aside for residential use on the San Mateo County coast is constrained by single-family zoning, attracting wealthy homeowners looking for large properties and small-town charm.
For low-income families, life on the coast looks different.
“The scenario that happens most commonly is that one family will sublease from another family,” said Judith Guerrero, executive director of Coastside Hope, a human services agency south of Devil’s Slide that provides support to working families seeking residency on the coast. “Sometimes you will have three families living in one, three-room trailer with one family in each room,” she said.
As efforts to increase opportunity housing spur ongoing debate, a report from the University of California, Berkeley's Othering & Belonging Institute suggests that single-family zoning contributes to racial segregation in the Bay Area.
The study's comprehensive analysis of zoning ordinances reveals that single-family zoning regulates development across more than 80 percent of Half Moon Bay’s residential land and over 90 percent of housing stock in Pacifica. Pacifica ranks among the top cities in need of reform in the Bay Area, according to the study’s authors.
"We're not talking about single-family homes," said Samir Gambhir, co-author of the publication. "We're talking about single-family zoning, and there's a difference."
Zoning is a common way to control land use in America. It determines how big a building can be, whether it is commercial or residential, if it's a single-family home or a high-rise. Single-family zoning prevents a community from building any type of housing except a detached single-family home in a given area.
"It's systemic," said Gambhir. "And it ensures that housing stays expensive."
The supply of housing in a given area is severely constrained when only one household can occupy a parcel of land, causing inflation in the housing market. Middle- and low-income families are kept out of neighborhoods where single-family homes are more expensive, while costs remain lower in denser communities.
Gambhir and his co-authors report that single-family zoning excludes residents of color who experience a persistent gap in earnings, making it much more difficult for them to compete for housing. The result is increased racial and economic segregation.
The study was released amid the state Senate’s discussion of various bills that would make it easier to build denser housing. SB 9 and 10 are currently awaiting the approval of Gov. Gavin Newsom.
SB 9 would allow property owners to subdivide their single-family lots to construct two duplexes or two houses with attached units. Cities and counties could approve buildings with up to 10 units on single-family lots under SB 10.
An analysis of SB 9 by UC Berkeley’s Terner Center for Housing Innovation estimates that it could help create 700,000 more units in the state's existing neighborhoods.
Guerrero echoed ongoing concerns that expanding multi-family zoning does not ensure that new units will be affordable. Instead, vulnerable homeowners and tenants may be displaced as developers purchase properties in hopes of building denser housing to turn a profit.
“I don’t think there is an easy answer,” said Guerrero. “You can expand housing but you have to make sure it’s affordable. But people need to make money so I’m not sure that would be the case.”
However, experts believe that successfully expanding opportunity housing would do more than just create more affordable places to live.
“It's not just to address the housing crisis; it's to ensure that people of varying income levels can build their wealth through homeownership," said Ilaf Esuf, housing and economic policy analyst for nonprofit United Way Bay Area. "It would become more affordable for families of color who are paid differently than white families and who have been historically left out of housing opportunities."
Since the beginning of the pandemic, housing has only gotten more expensive along the Coastside. According to data from the California Association of Realtors, Half Moon Bay home prices were up 24.3 percent compared to last year, selling for a median price of $1.88 million, while Pacifica home prices were up 17 percent compared to last year, selling for a median price of $1.47 million.
Many benefits traditionally accompany single-family neighborhoods — access to better schools, higher property values and higher incomes. Researchers attest that expanded opportunity housing in these neighborhoods would distribute these benefits more widely and equitably.
"People argue to keep single-family zoning to maintain neighborhood character,” said Gambhir. “This argument is used to hoard resources and ensure that they are used up within the community and not shared with people who are outside the current community.”
Results of the study indicate that access to these resources can have a long-term effect and lead to better life outcomes. Children who were raised in single-family zoned neighborhoods benefited from increased educational achievement, higher incomes and lower rates of poverty and incarceration in adulthood.
"We have to ensure that what we do for ourselves also impacts others. It's not a zero-sum game," said Gambhir. "It's not that, if you open up your doors to people from low-income communities, you're going to lose stuff. Sharing the resources can benefit everyone."