Los Altos makes changes to 'granny unit' law

More accessory structures and dwelling units could be popping up in Los Altos after the city council amended regulations last week, an effort aimed at easing the housing crunch.

An accessory structure is a nonlivable structure such as a pool house, shed or enclosed patio, while an accessory dwelling unit (ADU) – often referred to as a “granny unit” – is a backyard apartment someone physically inhabits. The amendments were brought before the council at its Feb. 27 meeting in part to comply with new state legislation.

The proposed changes to the accessory structure ordinance, which were reviewed by the Los Altos Planning Commission Feb. 1, included increasing rear-yard setbacks from the neighboring property and a rear-yard lot coverage limit of 35 percent.

According to Zachary Dahl, planning services manager for the city, the new setbacks – which would increase from 2 1/2 feet to 5 feet – would allow for more flexibility. He added, however, that as a structure gets taller, it would have to move farther away from the property line.

The real controversy came when the council discussed new red tape around converting accessory structures to ADUs. According to City Attorney Chris Diaz, the new law states that if property owners want to convert an existing nonconforming structure to an ADU, they are allowed to as long as they are not increasing the nonconformity.

“The state has basically tied local government’s hands,” Diaz said of the situation.

The council passed the accessory structure amendments 4-1, with Councilwoman Lynette Lee Eng dissenting.

Granny units for Los Altos

Amendments to the ADU ordinance required the council to review changes in order to comply with state law.

“There have been a number of recent changes at the state level that make it easier to get approval for secondary units,” Community Development Director Jon Biggs said. “The state has taken away some of the discretion that cities ... have in order to regulate accessory units, but the state is recognizing that there is a housing concern ... so they’ve decided to implement laws that streamline the process, expand opportunities for accessory dwelling units and reduce the parking requirements.”

Biggs added that changes also needed to be made to comply with the city’s recently adopted housing element and its minimum lot size requirement.

But reducing the lot-size requirement from 15,000 square feet to 10,000 square feet was slightly baffling when it came to the loophole about nonconforming structures being converted to ADUs.

“Isn’t the lot limit redundant?” Mayor Jean Mordo asked. “Essentially there’s no minimum-size lot for accessory structures, then by default automatically there’s none for this one, so we’re fooling ourselves.”

Biggs responded by noting that because of the way the state has written new legislation, property owners could essentially get away with secondary units on lots smaller than 10,000 square feet.

Affordable-housing crunch

Eng was particularly concerned with how Los Altos could use ADUs to help meet the city’s Regional Housing Need Allocation (RHNA) numbers, specifically citing affordable housing units.

While the state mandates that cities cannot impose affordability requirements on ADUs, Biggs said the city of Los Altos would need to conduct further research regarding how it would use ADUs to help the city meet its RHNA requirements. Biggs said he’s done some research on the city of Hillsborough, which has an aggressive ADU ordinance.

“What they have done is, they do an annual survey of all the accessory dwelling units that they have on record, and they don’t ask specific rents, but they ask for a range of rents for the accessory dwelling units,” he said. “Then based on the data that they get back, they’re able to say, ‘It looks to us based on the research that we’ve done that these accessory units meet certain levels of income criteria.’”

The council also wrestled with the attached versus detached ADU size limits. Diaz said that when the state passed Assembly Bill 494 last year, it made some clarifying changes for attached ADUs, allowing structures to be up to 1,200 square feet or up to 50 percent of the existing living area. The original language of the bill did not specify the 1,200-square-foot limit.

Councilwoman Jeannie Bruins, however, was concerned by the law in regard to its impact on the environment and the noise it could generate. She added that the amendments should be put on hold to allow Diaz more time to review the ordinance’s compliance.

In the end, the council voted 3-2 to pass the ADU amendments, with Bruins and Eng dissenting.

To view minutes from the meeting and for more information, visit

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