San Diego Multigenerational ADU with Office
Ainsley Road, San Diego, CA 92123
Homeowner Story: Downsize to ADU
A family in Mission Valley, San Diego, opted to build an accessory dwelling unit (ADU) for their own use while their family members move into the primary home. The 672 sqft ADU was based on a standard plan featuring two bedrooms of equal size, one bathroom with hall access, and an open-concept kitchen/living area.
For this ADU, some subtle customizations was all it took to make it the perfect dwelling, echoing the homeowner’s preferences, requirements, and lifestyle. After the build was completed, the family added the deck and trellis to expand the usability of the outdoor space. With four dogs in the family, they love having their homes connected so the dogs can visit each other, too.
“We are so glad we chose SnapADU to build our little house. Your teams have all been great & I so appreciate their follow up at every stage to correct details that I probably would not have been aware. We are happy to recommend SnapADU to anyone considering a project.” – Christine K.
Read more about multigenerational living.
Floor Plan:
2BR/1BA 32×21 Long
Community:
The City of San Diego ADU Guide
With more than 70 ADU projects completed or in progress throughout the City of San Diego, we’ve seen firsthand how the city’s regulations create opportunities that are not available in many other jurisdictions.
One of the biggest differentiators is San Diego’s Affordable ADU Bonus Program, which allows qualifying properties to add multiple ADUs when some units are rented at affordable rates. This has made San Diego a leader in ADU development and has opened the door for homeowners and investors to create additional housing beyond what is typically allowed under state law.
In 2025, the city became the first jurisdiction in San Diego County to adopt AB1033, allowing qualifying ADUs to be sold separately from the primary residence. As of June 2026, only the County of San Diego and the City of San Diego have adopted AB1033.
San Diego also offers significant flexibility in the types of ADUs that can be built. The city allows two-story ADUs, ADUs with garages, ADUs with guest quarters, ADUs with rooftop decks, front yard ADUs, and stacked ADUs for multi-unit projects. We’ve worked on all of these project types throughout the city.
Another unique aspect of San Diego is its setback regulations. Many single-story ADUs can be built with 0-foot side and rear setbacks, creating opportunities on properties where space is limited. However, building too close to property lines can trigger additional fire-rating requirements and construction challenges, which is why thoughtful site planning remains critical even when the regulations appear flexible.
San Diego ADU Permitting
Most ADU permits in the City of San Diego are approved within approximately 3 to 5 months after submission, although timelines vary depending on project complexity and city workload.
Compared to many other jurisdictions in San Diego County, the City of San Diego has some of the highest ADU permit fees. Permit costs often range from approximately $26-$28 per square foot, though smaller ADUs under 500 square feet can benefit from reduced fees closer to $14 per square foot. We maintain a detailed breakdown of City of San Diego permit fees, including plan check fees, building permit fees, impact fees, and inspection fees, in our ADU permit fee guide.
Approximately 10% of our City of San Diego projects are located within the Coastal Zone. While coastal properties often raise concerns for homeowners, many ADUs qualify for exemptions from Coastal Development Permit requirements under the City’s updated Local Coastal Program. Learn more about building an ADU in the Coastal Zone.
Working with an experienced ADU builder helps identify potential permitting requirements early and creates a more predictable path through design and permitting.
