California Law on Single-Family Lot Splits Ruled Unconstitutional

A Los Angeles Superior Court judge has ruled that a state law allowing property owners in California to split single-family lots and build additional units, a measure known as SB9, violates the state constitution.

SB9 was enacted in 2021 to address California’s housing crisis by opening single-family neighborhoods to higher-density housing. The law allows lot splits that enable homeowners to add up to three accessory dwelling units—also known as granny flats—on their property.

Last week, Judge Curtis Kin sided with five Southern California cities designated as charter cities—Redondo Beach, Whittier, Carson, Del Mar and Torrance—who sued in 2022 arguing that SB9 does not meet the standard required to impose the law on charter cities in the state.

More than 120 California cities are organized as charter cities, including Los Angeles, San Francisco and San Jose. Under California’s state constitution, charter cities have supreme authority over municipal affairs, meaning a city law can overrule a state law governing the same topic.

In order to impose a state law on a charter city, state lawmakers have to demonstrate that the law addresses a statewide concern. As written, SB9 says its purpose is “to ensure access to affordable housing.”

Attorneys for the plaintiffs argued that SB9 doesn’t require property owners to create affordable housing—which they defined as below-market-rate, deed-restricted housing—on subdivided single-family lots.

Judge Kin agreed, ruling that because SB9 doesn’t require the development of affordable housing, the law is unconstitutional.

The Superior Court judge’s ruling only applies to the five cities who sued, but if the ruling is upheld by an appellate court on appeal it will effectively overturn SB9 in all of California’s charter cities.

“We are reviewing the decision and will consider all options in defense of SB9,” the state Attorney General’s Office said, in a statement.

In his ruling, Kin said defendants in the lawsuit, including Attorney General Rob Bonta and the state housing department, failed to prove that SB9 will increase the number of homes affordable to low-income families “especially in economically prosperous cities.”

In a statement, Toni Atkins, a state senator representing San Diego who authored SB9, called the judge’s ruling “sadly misguided” and vowed to “remedy any loopholes” city governments might utilize to block new housing.

“The assertion by NIMBY city governments that SB9 is only about subsidized housing is a stretch at best,” Atkins said. “The goal of SB9 has always been to increase equity and accessibility in our neighborhoods while growing our housing supply and production across the state.”

A KQED survey of 16 California cities of varying sizes found that between 2022 and 2023, the cities collectively approved 75 lot-split applications and 112 applications for new units under the law.

In October, Gov. Gavin Newsom signed a law allowing accessory dwelling units to be sold separately—in other words, granny doesn’t have to live there—and for lower prices than full-sized homes. Metropolitan areas were permitted to opt out of that law.