California City Says It Can't Allow Duplexes Because It's Already Overrun by Mountain Lions

"Every house that's built is one more acre taken away from (mountain lions') habitat. Where are they going to go?" asks Woodside Mayor Dick Brown.


A California city says it can't approve new houses for people because it's already overrun by mountain lions.

Last week, the small Silicon Valley suburb of Woodside put an indefinite hold on approving new duplexes legalized by the recently passed state law Senate Bill (S.B.) 9, citing a provision in the legislation that excludes protected wildlife habitats. And the whole city, officials say, is a protected mountain lion habitat.

On Wednesday, the local Almanac newspaper reported on a January 27 memo issued by town Planning Director Jackie Young saying that mountain lions are a candidate for the state's protected species list. Because "Woodside – in its entirety – is habitat for a candidate species, no parcel within Woodside is currently eligible for an SB 9 project," wrote Young.

"We love animals," concurred Woodside Mayor Dick Brown in comments to the Almanac. "Every house that's built is one more acre taken away from (mountain lions') habitat. Where are they going to go?"

Where indeed.

S.B. 9 was one of several "yes in my backyard" (YIMBY) reforms passed by the California Legislature last year that attempts to address the state's housing shortage by paring back local governments' ability to block new housing construction.

It allows property owners to divide single-family zoned lots in two and build a duplex on each half—effectively allowing four homes where only one was permitted before. The law also requires local governments to approve these lot splits and duplexes "ministerially," meaning neither bureaucrats nor the neighbors can delay them with endless hearings.

Cities are often loath to cede their development-stopping powers to the state. Some have gone hunting for ways to nullify the actual impact of S.B. 9 while still complying with it on paper.

Enter Woodside, which is now clinging to a provision in the law that still lets localities ban duplexes on parcels identified as a "habitat for protected species."

The town's gambit is the most attention-grabbing effort by a municipality to keep duplexes out of its single-family neighborhoods. It's hardly the only one.

For instance, S.B. 9 also allows cities to restrict duplexes and lot splits in historic districts. So in December 2021, the planning commission in Pasadena suggested turning the entire city into a historic preservation district.

That same month, Sonoma passed an ordinance requiring that duplexes created under S.B. 9 be rented out at affordable rates to low-income tenants, or sold to moderate-income buyers. Because these affordability mandates require property owners to rent or sell new duplex units at well-below-market rates, they create a real disincentive to actually build them.

The numerous other carveouts built into S.B. 9 mean that many local governments don't have to take much action at all to minimize the impact of the law, says Dylan Casey, executive director of the California Renters Legal Advocacy and Education Fund (CaRLA).

"There are large areas of the hills in the Bay Area and in [Southern California] that are very high severity fire zones and those are all exempt. Historic districts are all exempt. It's a policy problem," says Casey. "All of these areas allow for single-family homes. So they are areas that are in the judgment of the local government that are appropriate for people to live in."

None of this is unprecedented. Housing politics in California has long been a cat-and-mouse game between a state government that periodically tries to boost housing production and local governments that try to prevent those new homes from popping up within their borders at all costs.

For instance, the first California law deregulating the construction of accessory dwelling units (ADUs)—alternatively called granny flats, in-law suites, or casitas—dates back to 1982. Cities still found ways of blocking these units by imposing infeasible height and size limitations on them, requiring they come with off-street parking, or slapping them with prohibitive fees.

It took the passage of another 13 bills over 37 years paring back those regulations and fees to make it truly feasible for your average homeowners to turn their unused garage or backyard shed into a new unit of housing.

"If cities are given opportunities to put up barriers to some of these laws, a lot of cities will take those opportunities," says Casey.

He says the state is at a better starting point with S.B. 9. The law bars cities from adopting restrictive rules on the physical size and shape of duplexes. But municipalities still have a lot of wiggle room to block these new homes, he says, suggesting more legislative action will be needed.

And even the most pro-supply housing laws can be toothless if they go unenforced. Local governments can shoot down state-legal projects without consequence.

It took a lot of legal challenges from groups like CaRLA and the Pacific Legal Foundation, a libertarian public interest law firm, to force holdout local governments to stop enforcing their own, illegal regulations on ADUs.

The good news is as high housing costs have become a more salient issue in California, and as more people grok that zoning rules are to blame for those high costs, state officials have started to take a tougher line with "not in my backyard" (NIMBY) municipalities.

"All of this activity from the private, nonprofit sector has inspired the state to get their butt in gear," says Sonja Trauss, executive director of YIMBY Law, which also sues cities for illegally shooting down housing projects. "It was always the case that the attorney general's office could do enforcement, but they just hadn't."

In November, California Attorney General Rob Bonta announced the creation of a 12-person unit within the state's Department of Justice to enforce state housing and tenant protection laws. The state's Department of Housing and Community Development has also created a new Housing Accountability Unit to enforce housing laws.

It's already sent a number of letters warning San Francisco that its constant delays of two zone-compliant apartment projects likely violate state law. (YIMBY Law is suing San Francisco over the city's denial of those same projects.)

Experiences from around the country show that eliminating single-family-only zoning laws in a way that actually leads to more housing construction is tricky business. Done right, it can produce some remarkable results.

California's long efforts to legalize ADUs have at last led to what CityLab describes as "a backyard apartment boom." Homeowners are able to get permits within a couple of hours and build a new unit in a couple of months. Builders are employing new technologies and methods to bring costs and construction times down even further. This is what happens when you don't regulate a product to death.

The hope is that a combination of increasingly pro-supply state housing laws, and more aggressive public and private enforcement of those laws, will lead to a similar duplex revolution. Perhaps a few could even be set aside to house mountain lions.