A 610-square-foot accessory dwelling unit in a Berkeley backyard. Credit: New Avenue Homes

Homeowners throughout the Berkeley flats could get quick approval to build backyard cottages that stand up to 20 feet tall after the City Council endorsed a new set of regulations for accessory dwelling units late Tuesday night.

But council members did not reach a decision on one of the thorniest questions facing their effort to write new rules for ADUs: how to regulate projects in the city’s fire-prone hills.

The council instead asked the city attorney and other departments to come back next month with more guidance about how much authority Berkeley has over those projects in light of new state ADU laws, which slashed local power to reject proposals. Some officials and residents have called for Berkeley to enact strict limits on new ADUs in the hills, arguing that more homes and residents will make it harder to evacuate people during a wildfire; others have countered that the city is risking a costly legal battle with the state if its rules violate the new laws, and say cracking down on ADUs won’t make the hills meaningfully safer.

“I do not feel that we have before us the kind of certainty we need around what is legally feasible,” Councilmember Sophie Hahn said near the end of more than three hours of public comment and discussion. “We need to give our legal staff the opportunity to analyze this.”

The council unanimously approved the provisions of a new ADU ordinance that would apply in lower-risk neighborhoods outside of the hills. The rules cover an area the city calls Fire Zone 1, which stretches from the San Francisco Bay to the base of the hills and includes West Berkeley, downtown, nearly all of South Berkeley and parts of North Berkeley.

For those neighborhoods, the council adopted a set of provisions drafted by Councilmember Rashi Kesarwani that would allow homeowners to build studio or one-bedroom ADUs with up to 850 square feet of living space, or two-bedroom units with up to 1,000 square feet. Homeowners could also make additions to an existing structure, such as a garage, up to those size limits.

Kesarwani said allowing ADUs that are up to 20 feet tall will give homeowners the option to save open space in their yards by building a two-story unit with a smaller footprint. She said she hoped the changes will have the effect of “incentivizing homeowners who previously may not have considered an ADU to consider one.”

“This flexibility will make it easier and cheaper and more desirable to create ADUs,” Kesarwani said, “so I hope we will see an increase in permits issued.”

The update to Berkeley’s regulations was prompted by state laws passed in 2019 that required local governments to grant “over-the-counter” approval to ADU projects that met broad criteria, meaning homeowners would no longer have to go through a lengthy notice or review process. The laws were meant to further boost the already rising popularity of ADUs, which supporters see as an easy and less-expensive way to build more homes and ease California’s housing crisis.

Kesarwani’s proposal — which was co-sponsored by councilmembers Ben Bartlett, Terry Taplin and Rigel Robinson — goes a step further than the baselines laid out in state law, which bars cities from enacting ADU height limits lower than 16 feet or size limits of less than 800 square feet.

Among other provisions, Kesarwani’s proposal would also allow certain items, such as water heaters or awnings, to protrude into a mandatory four-foot setback between an ADU and surrounding property lines, a measure she said would make it easier for homeowners with smaller lots to build units.

While some of the dozens of people who spoke about the regulations during public comment supported Kesarwani’s effort, others didn’t want the city to make it easier for property owners to build bigger ADUs.

“We see how awful some of these places can be,” said Berkeley Neighborhood Council executive Janis Ching, citing the example of a controversial ADU outside an apartment building on Harper Street in South Berkeley, which prompted an outcry from neighbors and tenants. “I want to urge you to start small and give us a chance to see what will be built.”

The council also endorsed a proposal from Robinson to create a new system for notifying existing tenants if their landlord is planning to build an ADU on their property, which was one reason the Harper Street project drew complaints. It’s not yet clear whether property owners will be required to provide that notification, or if the city will send out notices.

With those provisions approved, city staff will draft an updated ADU ordinance and bring it back to the council for final adoption.

And although the council pushed back consideration of a full set of rules for the hills, it separately updated Berkeley’s fire code to add a requirement that new ADUs in those neighborhoods include sprinkler systems. Under the rule, homeowners who add an ADU — or make additions or alterations valued at over $100,000 — would have to install sprinklers both in the new structure and in their existing home. Several members noted that provision, which could add tens of thousands of dollars to the cost of projects, would likely have the effect of deterring ADU construction in higher-risk areas.

Until the council acts to update regulations for the hills, the broadly permissive rules set out in state law will be in effect for those neighborhoods.

“While we do need to build housing as a city, we also have a responsibility to protect the health and safety of our community,” Mayor Jesse Arreguín said of the balance Berkeley wants to strike with rules for the hills. “Those two things are not mutually exclusive.”

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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,...