San Diego’s Accessory Dwelling Unit (ADU) program has been successful in enabling greater housing density within single-family and multi-family zones. However, the Bonus ADU program in single-family zoned neighborhoods, which allows an unlimited number of ADUs on parcels designated within the Sustainable Development Area, has had a profound negative impact on neighborhoods, with predictable community backlash.
In response, the City Council on March 4 asked the Planning Department to present revisions to the program to address the over-sized scale of some projects in single-family zones. The Planning Department’s proposals have been reactive and convoluted, in no small part because the Planning Department has not provided a comprehensive public input and review process.
A real revision of the Bonus ADU program would start with a foundational question — what role do we want single-family neighborhoods to play in providing new options for infill housing?
Proponents of the Bonus ADU program reflexively cite that we have a housing crisis that justifies building any kind of housing anywhere in San Diego. However, San Diego’s affordable housing needs are more nuanced than that. San Diego’s focus on total units rather than type of units means that San Diego struggles to provide family-sized housing.
Housing incentives and returns on investment are highly skewed towards smaller sized units — studios and one-bedroom units — in new developments. At the same time, the conversion of single-family homes into vacation rentals, urban containment based on flawed climate action policies, the California Legislature’s failure to address construction defect litigation, and the upward pressure on single-family home prices due to speculation in Bonus ADU development all conspire against family formation and family housing.
This critical problem is so important and overlooked in San Diego’s housing policies, that local housing expert London Moeder Advisors dedicated a 2022 report to highlight this topic, stating that “if policy is going to assume that families will transition to multifamily units, then 100% of recent multifamily growth should have been units with multiple bedrooms. This is the housing crisis linkage that is ignored in today’s environment and political landscape. It is also a driving force behind people leaving the state.”
There is a straightforward solution to this problem. To ensure that projects are consistent with their surrounding neighborhoods and to provide certainty for both developers and homeowners, Neighbors For A Better San Diego has aligned with the Community Planners Committee and other community advocacy groups to propose that the bonus regulations in single-family zoned neighborhoods be updated to eliminate the unlimited ADU bonus based on the Sustainable Development Area (SDA). As a result, the Bonus ADU bonus regulations currently in place for areas outside the Sustainable Development Area would apply to all single-family zones.
Numerically, this would result in the allowance of four dwelling units on any single-family property (main house plus three accessory dwelling units). This is consistent with the general definition of single-family development, such as the one used by the federal Department of Housing and Urban Development. It would also allow ADU development to continue to grow in San Diego. As noted in the May 9 Planning Department staff report presented to Land Use and Housing, 98% of projects with ADUs produce three or fewer ADUs, consistent with this proposal.
Instead of trying to build every kind of housing in single-family zones, capping the number of units as proposed would incentivize building larger, family-sized ADUs. This would put families in single-family neighborhoods that are uniquely suited to meet their needs.
The Planning Department’s report to the Planning Commission dated April 24, 2025, includes discussion of the City’s Neighborhood Homes for All of Us Initiative, which would the development of small-scale multiple unit buildings, including new for-sale housing. Because housing development gravitates to the highest allowed number of units, restraining the Bonus ADU program is critical to provide economic space to encourage these developments.
This initiative presents an opportunity to reintroduce a long-missing scale of housing — duplexes, fourplexes, courtyard buildings — that truly fits within and is compatible with existing neighborhoods and expands housing choice. This missing middle housing can be a valuable contributor to addressing San Diego’s housing needs, but only if the ADU Bonus Program is brought into appropriate scale.
Hueter is chair of Neighbors For A Better San Diego and lives in Talmadge.
