New California Duplex Law Permits Development in Residential Neighborhoods

Senate Bill 9, a California law scheduled to take effect January 1, will allow multi-unit housing in neighborhoods previously reserved for single-family homes, but some cities are fighting back with new restrictions. The law will require communities to allow the construction of duplexes, and in some cases four units, in most single-family residential neighborhoods in an effort to combat a state-wide housing shortage.

Opposing cities like Los Altos Hills, Cupertino, Pasadena, and Redondo Beach are rushing to pass regulations limiting size and height of new development, mandating parking spots, and requiring that multi-unit housing be rented only to those making moderate or low incomes.

“We want to ensure that we put in the few constraints that are allowed,” said Redondo Beach Mayor Bill Brand, whose city is considering capping the number of homes allowed amid other provisions. “It’s all happening very quickly and haphazardly as people are trying to figure out what they can and can’t do.”

It’s hard to overstate how big of a change the new law could have in California. Nearly two-thirds of all the residences in the state are single-family homes. And as much as three-quarters of the developable land in the state is now zoned only for single-family housing, according to UC Berkeley research. Additionally, the “California Dream” has long been mythologized as living in a suburban single-family home with a backyard and barbecue.

When Gov. Gavin Newsom signed the law in September, the state became the second in the nation to eliminate single-family-home-only zoning in most areas, following Oregon, which did it in 2019.

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