SAN FRANCISCO—Accessory Dwelling Units/ADU conversions are now legal throughout California, thanks to landmark by-right ADU laws signed by the governor in 2017 and 2020 that address the state's housing crisis. These laws not only give Californians the tools to ease the housing crisis, but more imminently, the health crisis.

"It is heartening to know that there was strong and widespread legislative support for these groundbreaking laws that deliver clear benefits to needy households in California, but the California ADU by-right laws are so recent that many Californians are unaware of them," Denise Pinkston, partner, TMG Partners, and founder/president, The Casita Coalition, tells GlobeSt.com. "ADUs, also known as grannie flats or second units, are cheaper to build, attractive to renters who want to stay in their neighborhoods and now are easier than ever to create."

In 2017, California legalized the conversion of existing buildings such as garages and basements on single-family lots to ADUs. On January 1, 2020, this law expanded to allow every single-family homeowner to add both an ADU and a junior ADU, including a new structure in the yard. Specs can include a new 800-square-foot freestanding 16-foot-tall structure within 4 feet of back- and side-yard lines, regardless of lot coverage or other zoning requirements.