An accessory dwelling unit built behind a home in Berkeley. Credit: Dan McDunn Credit: Courtesy Dan McDunn

Councilmember Susan Wengraf thinks accessory dwelling units are a great idea for most Berkeley neighborhoods.

But in the hillside district she represents — where fire authorities and residents fear what could happen if a fast-moving wildfire forces thousands of people to evacuate along narrow, winding roads — Wengraf contends backyard cottages and in-law units will add to the risk of a catastrophe.

That’s why, as Berkeley leaders update local regulations for ADUs to comply with new state legislation that aims to boost their production by streamlining the approval process, Wengraf is pushing for those rules to include tight restrictions on new units in the hills. It’s a stance that could lead Berkeley into a legal battle with the state, because California’s new laws limit local authority to reject ADU projects.

Similar debates are also playing out in Oakland and other cities with neighborhoods at risk from fires, forcing local leaders to grapple with two of California’s most pressing challenges: the housing shortage and wildfires that are growing more destructive in part because more people are living in fire-prone areas.

“What I’m trying to do is balance the need for more housing with the need for public safety, health and welfare,” Wengraf said. “Berkeley needs to be at the forefront of setting the example for other cities to figure out a way to reach that balance.”

The City Council is set to discuss ideas for new ADU regulations at its meeting Tuesday, a week after the Bay Area marked the 30th anniversary of the deadly Oakland-Berkeley Firestorm, and as rains bring this year’s fire season to an end. A final vote is expected later this fall.

The ordinance update is also expected to include tweaks to a long list of other rules for ADUs, including height limits, design standards and how close they can be built to property lines. Those factors have led to disputes between property owners who want to build ADUs and neighbors and tenants who object to them, such as at one project on Harper Street in South Berkeley.

Supporters view the units as a less expensive or obtrusive way to house more people on single-family lots, which could help cities such as Berkeley reach an aggressive regional target to plan for nearly 9,000 new homes by 2031. ADUs have become increasingly popular as Berkeley officials have loosened restrictions on them — the city granted 119 permits for accessory units in 2020, up from 16 permits in 2016.

Law gives cities less power to block ADUs

A law Gov. Gavin Newsom signed in 2019 could take that production to the next level: AB68 requires local governments to grant “over-the-counter” approval for ADU projects that meet certain broad criteria, saving homeowners the time and cost of going through public hearings or a design review process.

“The price of ADUs is still the main constraint, but it will make it easier (and) more straightforward,” Debra Sanderson, co-chair of Berkeley’s ADU Task Force, said of the law. “You’ll see more people wanting to build an ADU.”

The legislation also limits cities’ power to regulate ADUs: local laws can’t set height limits for the structures that are less than 16 feet and can’t cap their total area at less than 800 square feet, among other provisions. Jordan Klein, the city of Berkeley’s planning director, says there are “essentially no exceptions allowed” for local zoning rules to prohibit ADU construction.

Many housing advocates cheered these provisions, because they mean cities that have fiercely resisted growth will have substantially less power to block ADUs. But to Wengraf, the law is dangerously inflexible.

“The state has made it very difficult for us to tailor the ordinance to specific situations, like the situations we have in the hills,” she said.

Fire officials have zeroed in on the challenge of evacuating people from the hills in recent years, especially since the 2018 Camp Fire. The rush to evacuate the town of Paradise quickly led to gridlock as thousands of people tried to flee along a handful of routes to safety; some of the 85 people killed by the fire were found trapped in their cars.

Fearing the same kinds of traffic jams could develop here, the Berkeley Fire Department now encourages residents to leave the hills preemptively on the handful of days each fall when strong off-shore winds raise fire danger to critical levels. With climate change extending Northern California’s fire season and helping to fuel more intense blazes, the last thing Wengraf and others want is to add more people and cars to the hills.

“It is already getting too dangerous here,” George Porter, a hills resident and member of the city’s Commission on Aging, said in public comments about ADU regulations at a recent Council meeting. “We should just forbid ADUs in those areas.”

In Oakland, the Planning Commission has recommended a set of rules that would ban detached ADUs, such as cottages, from most properties in the hills; homeowners would still be allowed to build “internal” accessory units, such as by converting their basement into an apartment. The Oakland City Council has yet to act on that proposal.

A set of recommendations for new ADU rules passed by Berkeley’s Planning Commission earlier this year doesn’t go that far. But in areas at greatest risk from fires, Klein says the regulations would allow for only “what we’re forced to allow” under state law.

In Fire Zones 2 and 3, which cover the hills, the city would impose the lowest size limit allowed under state law, 800 square feet. In Fire Zone 1, which covers the rest of the city, homeowners could get over-the-counter approval for ADUs with two or more bedrooms of up to 1,000 square feet.

Will Berkeley court conflict with state?

Wengraf believes those recommendations don’t go far enough and wants Berkeley to enact more stringent limits in the hills. The specifics of her proposed regulations are still being worked out, she said, but will be part of the Council’s discussion on Tuesday.

Sanderson, a co-founder of the Casita Coalition, which lobbies for regulations that make it easier to build ADUs, said she believes the Berkeley Planning Commission’s recommendation strikes the right balance.

Efforts to further restrict construction in the hills are misguided, Sanderson argues, in part because construction and insurance costs already limit the number of ADUs that would feasibly be built there. Data from the Department of Planning and Development shows Berkeley issued 47 permits to build ADUs in the Fire Zone that covers most of the hills between 2018 and 2020, which represents 16% of the 292 ADU permits issued citywide in those years.

Sanderson also questioned whether the additional residents who would live in new cottages would make it significantly more challenging to evacuate the hills, where thousands of people already live.

“We are not going to have that many ADUs built in the hills, even if you let everybody build them,” Sanderson said. “Fire safety is such an emotional topic that it’s hard to find a middle ground that people can accept.”

Trying to enact too severe of restrictions could put Berkeley out of compliance with state law, Sanderson warned, the result of which could be that “we’re going to spend another two years in lawsuits.”

That was a concern for Mayor Jesse Arreguín, who said he wants more guidance from the state’s Department of Housing and Community Development on how Berkeley and other local governments can regulate ADUs in high-risk areas.

“A lot of it depends on what we can do legally — that’s really the central question that we need to figure out,” Arreguín said. If Berkeley wants to adopt more strict rules, he said, leaders will need to “really weigh the benefits of taking a position that may put the city at legal risk.”

Wengraf acknowledged a court battle with the state is a possibility but says it’s one she is willing to take on.

“There are some fights that are worth fighting,” Wengraf said. “Is the safety of our residents worth fighting for? To me, it is.”

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Nico Savidge joined Berkeleyside in 2021 as a senior reporter covering city hall. Born and raised in Berkeley, he got his start in journalism at Youth Radio as a high-schooler in the mid-2000s. Since then,...