State law has turned to ADUs to help address the housing crisis. But how many are actually used for housing?

Vista resident Liz Ream built an ADU next to her home to use as a commercial photography studio.
Vista resident Liz Ream built an ADU next to her home to use as a commercial photography studio, which has helped her spend more time with her three children.
(Luke Harold )

From home offices to art or photography studios, some homeowners put ADUs to use in a number of interesting ways


From home offices to music studios, California homeowners have found a number of creative reasons to build accessory dwelling units in their yards.

But regardless of what they’re used for, ADUs all have one thing in common: State law counts them as housing units, even when they’re not used for housing.

That discrepancy has implications for a statewide process known as the Regional Housing Needs Allocation, which assigned every local government a number of new housing units that they need to accommodate in their housing elements between 2021 and 2029. City and county officials can count all ADUs toward their allocations without having to verify whether a given ADU will actually hit the housing market during that timespan, according to the state’s Department of Housing and Community Development.

ADUs, also known as casitas or granny flats, have historically been used as inexpensive housing for students, older relatives or other family members. With the ongoing California housing crisis, lawmakers have passed laws over the last few years to simplify ADU construction requirements with the goal of providing more housing for a wider array of potential tenants. State law requires ADUs to meet the standards of a livable unit by having components such as kitchens and bathrooms, but there’s no law that says anyone has to actually live in them.

A map of ADUs that have been built, or are in the process of being built, over the last few years throughout coastal North County (Luke Harold)

Based on interviews with contractors and homeowners, most ADUs are used as rental units or to house family members. But other homeowners have put them to use as home offices, art studios, and other purposes that further their work-life balance or support a hobby.

Liz Ream, who lives in Vista with her husband and three children, completed an ADU on her property in fall 2021, after hiring a contractor and completing a construction process that lasted about six months. She uses it as a studio for her commercial photography business.

“We were just looking at ways that I could be home more and still contribute to our finances,” she said.

Ream said she first thought about adding a shed to her property, but decided that an ADU would be a better investment.

The county government counted her ADU as a moderate income unit in its annual housing progress report, since she lives just east of Vista city borders in unincorporated San Diego County.

San Diego County received an assignment of about 171,000 new units for the current RHNA cycle. The county’s unincorporated territories have to accommodate 6,700 of those units, including 1,165 moderate income units.

Whitney Hill, co-founder of Oceanside-based ADU contracting company SnapADU, also said appraisal value is a strong motivator to build an ADU, even if there are no plans to rent it to a tenant.

“They also gain more flexibility to rent the unit down the road, which also supports a better resale value,” said Hill, whose company built Ream’s ADU.

Derek Berg, founder and president of MADesign and Drafting Services, said the ADUs his company has built throughout San Diego can be broken into thirds: one third use them for a family member, one third use them as rental units, and the final third use them for other purposes. He said he’s built a few as music studios and other “fun” ideas that help his clients personalize their properties.

“My clients are spread across the board when it comes to the intent,” Berg said. “But those are the three big reasons I’ve run into.”

ADUs and new laws that streamline their construction pose another set of concerns in coastal cities, where new development is typically scrutinized for impacts such as ocean view blockages.

“The state law is all about allowing ADUs to cut corners to jump to the finish line without going through the normal process on the premise that they were going to provide housing,” Del Mar Mayor Dwight Worden said. “But if you’re not requiring people to live in them, you’re not getting that benefit.”

According to Del Mar’s 2021 housing element annual progress report, the city has 27 ADUs so far that will count toward its sixth cycle RHNA requirement of 163 housing units. Based on a review of the development applications, 12 of those homeowners indicated that they do not plan to rent their ADUs.

Worden authored a proposed amendment to state law that would allow cities to draft their own ordinances that require ADUs to be used as housing units. He shared it with the League of California Cities, and said during a recent council meeting that the city could try to find a sponsor in the Legislature.

Assembly members Tasha Boerner Horvath and Chris Ward, both Democrats whose districts include coastal North County, declined comment. Nathan Fletcher, president of the county board of supervisors, also declined comment.

State Senate President Pro Tem Toni Atkins, D-San Diego, said in a statement: “While my office was not previously aware of this issue, we will be monitoring it going forward.”