California is grappling with a severe housing shortage, where accessory dwelling units (ADUs) are becoming a vital part of the limited increase in new homes.
According to data analyzed by The Times, the state’s housing stock saw a modest growth of only 0.84% in 2024, translating to approximately 125,000 new units.
ADUs accounted for around one-fifth of this growth, as reported by the California Department of Finance.
The trend of ADU construction has surged in several areas, with many homeowners opting to create a secondary housing unit on their property.
Although the construction costs for these units can reach hundreds of thousands of dollars, many homeowners view them as valuable investments that boost their property’s worth.
However, ADUs differ significantly from large-scale apartment buildings or other new residential developments.
Some owners choose not to rent out their ADUs, using them for family members or leaving them unoccupied.
This uneven popularity across different California regions raises questions about the effectiveness of ADUs in alleviating the housing crisis.
Eric McGhee, a senior fellow at the Public Policy Institute of California, pointed out the complexity in determining whether ADUs are successfully housing individuals who would not otherwise have accommodations or if they merely provide additional space for existing residents.
This ambiguity suggests that while some ADUs may contribute to the housing supply, others might do little to ease demand.
A study by the San Diego Association of Governments revealed that 85% of the permitted ADUs in the county are occupied by renters, leaving only 15% for owner occupancy.
Nonetheless, many occupied units might simply be used by people already living on the property, complicating the overall impact on the housing market, McGhee noted.
He posed a critical question: “Is it enough to just build anything, or do we need to focus on constructing housing that better meets demand?”
In recent years, the production of ADUs has seen substantial annual increases, with a 14.3% growth in 2024 compared to the previous year, reflecting a consistent upward trend following a 10% growth in 2023.
Despite stable statewide housing growth, the increasing contribution of ADUs indicates their rising significance in the housing landscape.
Analysis of state data reveals that Los Angeles City increased its housing stock by 6% from 2020 to 2025, ranking as the third-highest among the 88 cities in Los Angeles County.
Only the cities of Duarte and Monrovia experienced greater proportional growth.
In stark contrast, cities like Avalon, Westlake Village, and Cerritos saw minimal to no growth during the same period.
Throughout Los Angeles County, the housing stock grew by 3.75% over five years, closely mirroring the statewide figure of 3.87%.
Conversely, certain fast-growing counties in California have outperformed Los Angeles significantly.
For instance, Madera County reported a housing stock growth of 2.7% in 2024, while Placer and San Benito counties approached around 2% annual growth.
Smaller but rapidly growing cities demonstrated even more pronounced growth; for example, Huron, located in Fresno County, recorded an impressive nearly 8% increase in housing stock in 2024.
Other cities like Lathrop (San Joaquin County), Winters (Yolo County), and American Canyon (Napa County) also reported growth exceeding 5% for the year.
Major metropolitan areas such as Los Angeles, Oakland, and San Diego have been relatively successful in generating new multi-unit housing complexes, primarily offering one- and two-bedroom rentals in their development efforts.
As urban environments become saturated, the suburban and peripheral cities like Huron are witnessing a rise in greenfield development, predominantly consisting of single-family detached homes.
Los Angeles County stands out as a hub for ADUs, with a 2024 analysis showing the county permitting more accessory dwelling units per capita than any other county in California.
The data also revealed that lower- and middle-income cities have been the most active in approving ADU construction.
Key cities permitting significant ADU developments include San Fernando, Rosemead, Temple City, Sierra Madre, and Hidden Hills, while those with the lowest permitted units are Hawthorne, Commerce, Cudahy, Cerritos, and Westlake Village.
Furthermore, a 2024 research project conducted by UCLA’s Lewis Center for Regional Policy Studies explored the western San Fernando Valley.
The study found that over 7% of single-family-residence parcels in the area were granted ADU permits.
Cressy’s research aimed to better understand the potential of ADUs in addressing California’s pressing housing crisis.
The findings indicated that the prevalence of ADUs tends to correlate with factors such as lower-income levels, renter-occupied households, and denser populations, alongside higher concentrations of non-white residents and registered Democrats.
Moreover, ADU developments were notably less common in hillside and fire-prone areas, suggesting their concentration in more climate-resilient regions of the state.
image source from：latimes
