Accessory dwelling units, or ADUs, are becoming a popular option for housing affordability where regulation allows them. Who better to live in the home on the same property than relatives or parents? This article from CALmattersexplores the growing trend in California. How will it translate across the country?

Paul Boehm wasn’t sure how his daughter would react to the idea of moving into her childhood backyard.

The 63-year-old retired San Jose school teacher thought there was a good chance Daniela and her husband, Rigoberto, would instead join the growing exodus of young Bay Area families heading east to the more affordable Central Valley. They already had seen a few Sacramento properties with a Realtor, and liked what their middle-class salaries—Daniela a special ed teacher, Rigoberto a family counselor for a nonprofit—might be able to buy there.

Paul and his wife, Rosa, 60, didn’t want to travel that far to visit any future grandchildren.

So they approached their daughter with a proposal: They would build a 538-square foot Accessory Dwelling Unit—colloquially known as an in-law unit, granny flat or “ADU”—in the backyard of their west San Jose home.

The Boehms are one of a growing number of California seniors turning to ADUs as a solution to the challenges of aging in a very expensive state—often by moving into the backyard units of their adult children, or by having their adult children move into theirs.

After state laws passed in 2016 and 2017 made it easier and less expensive to build them, ADU’s have exploded in popularity in many cities. Los Angeles received about 67 times as many ADU applications last year compared to three years ago, according to data collected by the UC Berkeley Terner Center for Housing Innovation.