The San Diego City Council voted 5-4 on Monday to impose new restrictions on accessory dwelling units (ADUs), setting up a possible confrontation with state housing officials who warned the changes could violate state law.

Included in the package of reforms proposed by the City Planning Department are new fees to pay for infrastructure, parking requirements for properties far from public transit and restrictions on cul-de-sacs and in wildfire hazard zones.

The greatest change to the program is a new cap on the number of ADUs a homeowner can build in their backyard. The city’s ADU bonus program currently has no such cap, but does restrict the number of ADUs based on lot size, height limit and other zoning regulations.

Councilmember Henry Foster III proposed a cap of four ADUs for lots that are 8,000 square feet or less, five ADUs for lots between 8,001 and 10,000 square feet and six ADUs on lots of 10,001 square feet or more. The standard lot size for a single-family home in the vast majority of San Diego is 5,000 square feet.

An earlier motion that would have limited all properties to four ADUs failed to win a majority. Foster’s motion passed 5-4 after Council President Joe LaCava switched his vote to “yes.” Also voting “yes” were Councilmembers Jennifer Campbell, Marni von Wilpert and Raul Campillo. Councilmembers Stephen Whitburn, Kent Lee, Vivian Moreno and Sean Elo-Rivera voted “no.”

“ADUs (are) part of our housing solution,” LaCava said after more than four hours of public testimony, most of it in opposition to large ADU projects. “But it doesn’t mean that it shouldn’t be right-sized.”

Also included in the package of reforms is an allowance for homeowners to sell off ADUs separately as condominiums.

Mayor Todd Gloria and the council have been under pressure to scale back the ADU bonus program, which has led to some projects with a dozen or more ADUs on a single property. Homeowner groups say such projects reduce privacy, constrain parking supply and alter the visual character of suburban-style neighborhoods.

Neighbors for a Better San Diego, the group leading the opposition to the ADU bonus program, sent an email Monday night saying the council’s reforms were “not perfect, but definitely better.”

“It’s not the ‘4 is Fair Everywhere’ that we had hoped for,” the email said, referring to the group’s preference for a citywide cap of three ADUs per property in addition to the primary residence. “But it will greatly reduce the damage that has been done to neighborhoods by predatory investors under this program.”

Last Friday, the state’s Housing and Community Development Department (HCD) sent San Diego a letter threatening to find the city in violation of state law if the reforms were approved as presented. The ADU bonus program is a component of the city’s strategy to undo the racist and discriminatory housing policies of past generations, the letter argues, and reducing its scope could hinder those efforts.

City staff, who said the letter took them by surprise, swiftly revised their recommendations, agreeing to keep the ADU bonus program in place in wealthy, low-density neighborhoods such as Point Loma, La Jolla and Del Mar Heights where the program had been proposed for removal.

City staffers said they would respond to HCD in writing by the agency’s deadline of July 11.

“What the City Council approved closely aligns with the staff’s recommendation,” mayoral spokesperson Rachel Laing told KPBS. “We thank the council for their feedback and friendly amendments. We’ll continue to engage with the state’s Housing and Community Development agency to ensure San Diego’s housing element remains in compliance and that we maintain our prohousing designation.”

Defenders of the ADU bonus program say it has produced hundreds of lower-cost housing options in neighborhoods dominated by more expensive single-family homes, and that it’s creating affordable housing for the middle class with no subsidy from taxpayers.

“That’s incredibly meaningful to the people who live in those homes now, and I’m glad that they were built,” said Councilmember Moreno. “But it’s not enough. We still need more housing for families.”

San Diego permitted 5,720 ADUs between 2021 and 2024, according to figures shared by city staffers. Of those, 875 were permitted under the city’s ADU bonus program.

Saad Asad, spokesperson for the prohousing YIMBY Democrats of San Diego County, said the council’s reforms would make housing more expensive and harder to find.

“With one vote, City Council just made it harder to build affordable housing during a housing shortage,” Asad said. “They’ve effectively told San Diegans: Pay more to live here, or move farther out and sit in traffic.”