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October 11, 2021

Creating New Homes Through Accessory Dwelling Units: SDHC Program Provides ‘Lessons Learned’ to Help Property Owners

San Diego Housing Commission report available online today at

SAN DIEGO, CA — The San Diego Housing Commission (SDHC) has completed a pilot program to construct five Accessory Dwelling Units (ADUs)—sometimes referred to as “granny flats”—and provide “lessons learned” from the program to help San Diego homeowners considering ADUs, an important source of new housing needed in the City of San Diego.

“The rising cost of housing is far outpacing people’s income and the dream of owning a home is becoming more and more unreachable for families,” said City Councilmember Vivian Moreno, who represents Council District 8, the location of the five ADUs SDHC developed, and serves on the City Council’s Land Use and Housing Committee. “The findings from the pilot program will help homeowners throughout our city understand the process and costs associated with creating Accessory Dwelling Units on their property, which increases housing in our region.”

SDHC developed ADUs in the available yard space at five single-family homes SDHC’s nonprofit affiliate owns and rents as affordable housing to households with low income.

“Our Affordable Housing supply continues to be a critical issue affecting all San Diegans,” said Council President Pro Tem Stephen Whitburn, who chairs the City’s Land Use & Housing Committee. “The need for affordable housing far exceeds our housing production and has led to many of our residents being unable to afford living in our city. As the council and mayor continue to push for housing solutions, we must work together to overcome this crisis affecting San Diegans.”

SDHC published its report about the ADU pilot program on its website today at Additional information about ADUs is available on the City of San Diego Development Services Department’s website at

“ADUs are an important option available to create new rental homes to address the housing shortage in the City of San Diego,” SDHC President & CEO Richard C. Gentry said. “The lessons learned from the San Diego Housing Commission’s program will help homeowners understand cost, timelines and other aspects of development as they consider building ADUs.”

To develop ADUs in its pilot program, SDHC modified City of Encinitas Permit-Ready Accessory Dwelling Unit plans to ensure they fulfilled City of San Diego Municipal Code requirements. SDHC has submitted these final plans to the City of San Diego and, upon final approval, will make them available as permit-ready plans for other San Diego homeowners to use to facilitate the construction of ADUs.

The “lessons learned” from SDHC’s program include:

  • Assemble a team of experienced professionals for the design, permitting, and construction of the ADU.
  • Use permit-ready plans.
  • Consider factors that can significantly impact cost, such as units smaller than 500 square feet benefit from fee waivers in San Diego.
  • Prepare for factors that can significantly impact the project’s timeline, such as:
    • In the design phase, permit-ready plans can reduce the overall time for the architect.
    • A permit expediter can be hired to help with faster processing of permits.
    • A thorough site feasibility study in design phase helps avoid unexpected delays and construction changes.
  • Consider manufactured units as an option to reduce time and cost per square foot without compromising quality or design. Manufactured units are built off-site and then transported and placed on a permanent foundation at the property. One of the ADUs SDHC developed is a manufactured unit.

Cost estimates based on SDHC’s pilot program range from $116,803 for a 224-square-foot studio to $342,078 for a 1,199-square-foot, three-bedroom unit.

Timelines may range from 10 to 26 months, depending on the type of ADU (manufactured, permit-ready design/building plans or custom plans).

ADUs were identified as one of the five main sources of potential new housing in the City of San Diego over 10 years, through 2028, in SDHC’s report, Addressing the Housing Affordability Crisis: San Diego Housing Production Objectives 2018-2028. The number of ADUs permitted for construction in the City rose from 32 in 2017 to 266 in 2018 to 627 in 2019. In 2020, 493 ADUs were permitted for construction, according to the City of San Diego’s Annual Housing Inventory Report.

The State of California and the City of San Diego have facilitated and encouraged the production of ADUs as a strategy to address the shortage of affordable housing. This includes updates to the San Diego Municipal Code that reduced parking requirements, zoning setbacks and fire sprinklers, and waived Development Impact Fees, Facility Benefit Assessment Fees and General Plan Maintenance Fees.

SDHC worked with architect and general contractor Milo Hama of MJHama, LLC, to analyze elements of SDHC’s experience developing the ADUs during its pilot program. SDHC used this analysis to create the report of “lessons learned.”



Media Contact:

Scott Marshall

Vice President of Communications

San Diego Housing Commission


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