What does the City of San Diego’s ADU Bonus Program allow on one lot?
The City of San Diego’s Development Services keeps its ADU rules on one page. A single-dwelling-unit zone allows two ADUs plus one JADU, and multiple-unit and mixed-use zones allow two or more. An ADU runs 150 to 1,200 square feet, a JADU 150 to 500 inside the house. Parking is not required except for garage conversions in the Beach Impact Area, every unit needs a building approval, and a lot in the Coastal Overlay Zone follows a separate coastal ADU page.
The ADU Bonus Program is the affordability trade. Inside a Sustainable Development Area, each ADU deed-restricted for 15 years to a very low-, low-, or moderate-income household earns one market-rate bonus ADU, and lot area is the only cap. Outside those areas the bonus is capped at one, and two affordable ADUs may add a bonus accessible ADU. Every affordable and bonus unit needs fire sprinklers and, outside a transit priority area, one off-street parking space, and none can be sold separately: owners may condo-map ordinary ADUs, but not bonus-program units.
Setbacks decide the footprint. An ADU under 16 feet needs no side or rear setback outside a Very High Fire Hazard Severity Zone, a taller unit next to residential keeps four feet, and inside that zone four feet applies at any height. The City accepts pre-approved plans from the County of San Diego, Chula Vista, and Encinitas on a 30-day review, bars rentals under 31 days, and requires solar on a new detached unit. A San Diego homeowner who says “bonus ADU” means a multi-unit build, not a cottage.
City of San Diego Development Services, Accessory Dwelling Unit / Junior Accessory Dwelling UnitCity of San Diego or unincorporated County: whose desk reviews the job?
The County’s Planning & Development Services ADU page applies, in its first line, to the unincorporated areas of San Diego County. Chula Vista, El Cajon, La Mesa, Santee, Poway, Escondido, Vista, Carlsbad, Oceanside, and Encinitas are separate cities with separate desks, and the City of San Diego is another. Unincorporated communities such as Lakeside, Ramona, and Spring Valley answer to the County, which requires a residential lot with an existing or planned house, and its Director’s Determination Letter says state law wins where the Zoning Ordinance conflicts.
County size rules differ from the City’s at the margin. An attached ADU may reach 50 percent of the main house, capped at 1,200 square feet, with exceptions to the percentage but never the cap when the house has more than one bedroom. A detached ADU tops out at 1,200 square feet regardless of the house, and a JADU stays inside at 500 or less. The page lists detached, attached, above-garage, interior, and garage-conversion types, links an ADU Handbook, and offers County-drawn detached plans it calls approximately 85 percent complete.
Three notices matter. The County’s trial impact-fee waiver ran from January 9, 2019 to January 9, 2024 and has ended, so quote no waiver. Under AB 2533, an ADU or JADU built before January 1, 2020 without sign-off may qualify for streamlined legalization if it meets health, safety, and building standards, optionally after a confidential inspection by a licensed contractor. And on March 4, 2026 the Board of Supervisors voted unanimously to allow separate sale of ADUs in unincorporated communities through condominium conversion.
County of San Diego Planning & Development Services, Accessory Dwelling UnitsHow much of what San Diego builds is ADUs?
The City of San Diego’s 2025 Annual Report on Homes covers calendar year 2024 and counts 8,782 new homes approved, 1,061 of them, or 12 percent, deed-restricted as affordable. ADUs were 2,285 of those homes, a single-year record, and 26 percent of all homes citywide. The report traces the climb: under 1 percent of approvals from 2014 to 2017, 7 percent in 2018, 12 percent in 2019, 20 percent in 2023, then 26 percent. The ADU Home Density Bonus Program accounted for 653 ADU homes in 2024, and from 2021 through 2024 it produced 892, 370 of them deed-restricted.
The report maps where the units land. In 2024 the community plan areas with the most ADU approvals were Clairemont Mesa with 251, North Park with 204, Southeastern San Diego with 181, Linda Vista with 165, City Heights with 131, College Area with 127, Skyline/Paradise Hills with 117, Pacific Beach with 116, and Encanto with 112. Across 2021 to 2024 Clairemont Mesa led with 607 and North Park followed with 472, and 87 percent of 2024 ADUs sat near transit.
Single homes in the 2024 count were 100 percent above-moderate income, the report’s label for market-rate work. Against a 108,036-home regional allocation for 2021 to 2029, the City had approved 29,058, or 27 percent, and says it needs 78,978 more by 2029, roughly 9,800 a year. Less than 2 percent of the City’s land is both vacant and developable, so the report expects infill. For a contractor, that means backyard units, conversions, and replacement houses on lots that already have a neighbor.
City of San Diego, 2025 Annual Report on Homes