Starved for Inventory, Some Cities Eye ‘Granny Flats’

January 17, 2018

“Granny flats” or in-law units are surging in popularity in some housing-starved areas. Some lawmakers are leading the charge by changing laws to allow accessory dwellings units in backyards, converted basements, or garages of existing homes.

In the San Francisco Bay Area, the number of people applying to build these units has grown by more than 1,000 percent over the past year, due to a change in laws that now allow for these small dwellings. Accessory dwelling units typically are small structures that total under 1,000 square feet and are built on an existing property of homeowners.

Housing analysts expect the growth in these small dwelling units to be even more in 2018 as more legislators and local cities propose new, granny-flat friendly policies.

“This is going to be a major piece of the solution to our housing crisis in the next decade,” Matt Regan, senior vice president of public policy for the Bay Area Council, told the Mercury News.

In San Francisco, a senate bill became law last January that slashed the price for building an in-law unit (prior local impact fees could run up to $60,000 for some homeowners to build these).

“The growth has been pretty dramatic,” Steve Vallejos of Valley Home Development, a developer who specializes in in-law units, told the Mercury News.

But some critics are concerned about the growing number of in-law units. They argue that easing restrictions could lead to “impaired neighborhood character,” increase competition for parking spots in neighborhoods, and threaten the privacy of existing homeowners.

Dan Bertolet, a senior researcher at a think tank called Sightline Institute, says many neighborhoods are fighting against reforming building codes to allow for more ADU construction in his hometown in Seattle.

“Slowly and surely, more cities are adopting ADUs, more will be built, and we’ll realize Armageddon isn’t going to happen,” Bertolet told “This is a period of growing pains. That we can’t even do the gentlest, least intrusive kind of density change in a city suffering from a huge housing shortage is kind of mind-blowing.”

Source: “New Bay Area Housing Trend: Living in the Backyard,” The Mercury News (Jan. 16, 2018) and “Why Tiny ADUs May be a Big Answer to the Urban Housing Crisis,” (Jan. 16, 2018)