Building a cottage in your Berkeley yard? Just make sure to tell the neighbors.

Homeowners in the Berkeley flatlands can now build two-story accessory dwelling units in their yards — as long as they inform their neighbors and tenants first.

This ADU project on Harper Street in South Berkeley ignited a controversy in part because tenants and neighbors weren’t told about plans for the structure before construction began. Credit: Supriya Yelimeli

The Berkeley City Council approved a set of regulations for accessory dwelling units Tuesday night requiring tenants and neighbors to get a heads up if a property owner wants to build a cottage in their back or front yard.

The new rules will allow for homeowners in Berkeley’s flatlands to get near-automatic city approval to build ADUs that are up to 20 feet tall, an idea the council endorsed last fall. Meanwhile council members still have not decided how they want to regulate cottages in the Berkeley Hills, where concerns about wildfire risk have led some to argue the city should tightly limit their construction.

Under the new regulations, city staff will notify any existing tenants about plans for an ADU on their property, along with property owners or tenants of the parcel’s immediate neighbors, no more than 10 business days after a homeowner submits a project application. The homeowner who wants to build an ADU will be required to pay for the notices.

Any tenants or neighbors who oppose those plans likely won’t have the power to block or change them under Berkeley’s new rules, which were prompted by a 2019 state law mandating that cities grant “over-the-counter” approval to many ADU projects, without public hearings or a requirement to give notice. Still, Councilmember Rashi Kesarwani, who authored the local ADU regulations, said the notices would provide a courtesy that ensures projects don’t catch people by surprise.

“Given that reality, that these are projects that cannot be slowed down or denied, I think it’s appropriate that people are at least made aware of an ADU application,” Kesarwani said.

The requirement could help ease controversies like the one that unfolded last year over a South Berkeley project in which a landlord started building an ADU on top of an apartment building parking pad without telling his current tenants or neighbors. The lack of notice was only one of the reasons opponents took issue with the project on Harper Street, though, with neighbors complaining about the size of the 1,005-square-foot project and its location abutting the sidewalk in front of the apartments.

When it comes to the size of ADUs, Berkeley’s new rules are more permissive than those laid out in state law, which aimed to make it quicker and easier for homeowners to build projects by stripping California cities of much of their power to reject or delay them.

The state law set a baseline requiring cities to give ministerial approval to ADUs that are up to 16 feet tall, with 800 square feet of indoor space. For Berkeley homes in the area known as Fire Zone 1, which covers neighborhoods outside the hills, council members raised the limits for ministerial approval to 20 feet of height and 1,000 square feet.

At Tuesday night’s meeting, Mayor Jesse Arreguín and several other council members expressed reservations about setting the cap for over-the-counter approval at 20 feet, saying that would allow for “huge” ADUs with little public input.

While the popular image of accessory units has long been unobtrusive backyard cottages or “granny flats,” Councilmember Kate Harrison said the new state law and local regulations allow for bigger developments that should be subject to greater scrutiny.

“Our original thoughts about ADUs,” she said, “are kind of thrown out the window.”

Arreguín proposed lowering the height limit for ministerial approval to 16 feet and requiring homeowners who want to build 20-foot structures to seek a use permit, which requires a longer process. He later conceded, though, that his idea did not have majority support; Kesarwani’s regulations were approved unanimously.

Backers of the 20-foot height limit said it can allow for more varied ADU designs, giving homeowners an incentive to build vertically and preserve open space in their yards. Some neighbors may object to taller structures, Councilmember Lori Droste said, but subjecting those projects to a more drawn-out process will add to their costs, threatening efforts to build more homes and ease the housing crisis.

“Time is money, and this affects families,” Droste said. “It could rub people the wrong way — but contrast that with being able to house families in people’s backyards.”

Nico Savidge is Berkeleyside's senior reporter covering city hall. Email: nico@berkeleyside.org. Twitter: NSavidge.