As the cost of housing in San Jose continues to soar, the city is making it easier for residents to build small dwellings on their property — and, for the first time, they can have two bedrooms.

On Tuesday, the San Jose City Council voted on several zoning amendments that will allow more people to build what are commonly known as granny flats or in-law units in their backyards.

Until now, according to the Housing Trust of Silicon Valley, around 103,000 single-family lots in San Jose have been eligible for these accessory dwelling units. But interest appears to be growing.

According to a report from UC Berkeley’s Terner Center for Housing Innovation, building permit applications in San Jose for the units increased from just 28 in 2015 to 166 in 2017.

Not everyone who wants to build a granny flat has been able do so, however, with zoning restrictions and setback requirements limiting which properties can host them.

Resident Cecilia Shao has owned a home in San Jose for about 40 years and wants to build a granny unit for her elderly parents. Her lot is big enough, she wrote in a note to the City Council ahead of the vote, but the rules prohibited her from adding a flat.

“These changes would help families like mine better use our property,” Shao wrote, “and provide more and better quality housing stock in San Jose, which we all know is sorely needed.”

The council passed a series of changes, including allowing two-bedroom flats, which had been barred; permitting the units to be built on lots with high-density residential development, where they’d previously been restricted; allowing the dwellings to be slightly bigger; and reducing the lot size required to 3,000 square feet from more than 5,000.

According to the Housing Trust of Silicon Valley, the changes will make granny flats a possibility on an additional 18,000 lots. And the planning commission has said the changes will help add badly needed affordable housing within already developed neighborhoods “while maintaining the existing character and feel of these neighborhoods.” The units will also, advocates say, create new income opportunities for homeowners.

Vianey Nava, the Housing Trust of Silicon Valley’s accessory dwelling unit program manager, thinks the changes make sense. More dwellings mean more badly needed housing, and less restrictive regulations, financial incentives and education can help drive construction, Nava said.

“We think it could still go a lot further,” she said.

Right now, the city imposes certain parking requirements when people want to build granny flats. In a memo, Mayor Sam Liccardo suggested allowing residents in neighborhoods where there is “plentiful parking” to get waivers from the requirement. But it was unclear exactly what constituted “plentiful parking” and the council delayed that decision, asking the planning department to come back in the future with options for updating the parking requirements.

Councilman Johnny Khamis said at Tuesday’s meeting he foresees parking woes being one of the main complaints from residents as more people build the dwellings.

San Jose is not alone in updating its granny flat regulations. At the state level, lawmakers have passed several bills in the last few years that eliminate some barriers to building the units and are considering more changes, including possible amnesty for Californians who want to update existing unpermitted units. Santa Cruz waived water and sewer connection fees and fire sprinkler requirements in units attached to homes in 2014, and Campbell is considering eliminating its own lot size requirements.

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Liccardo has repeatedly touted a plan to build 25,000 homes — 10,000 of them affordable — in the next few years in San Jose, and sees the units as a key piece of that plan.

“With the help of our willing neighbors who own single-family homes,” Liccardo wrote in his memo, “we can put some small dent in the obstacles faced by our underhoused community.”

Staff Writer Marisa Kendall contributed reporting.