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ADUs In San Diego

Last updated November 3, 2026

The City of San Diego began accepting pre-approved companion and junior unit plans in 2019, according to a city news release, and applicants may still need site-specific plans. The Terner Center survey found a median construction cost of $130,000 for Orange and San Diego Counties together.

The Local Program

The City of San Diego began accepting pre-approved companion and junior unit plans in 2019, according to a city news release. The release says applicants may still need site-specific plans and calculations. Check the Development Services Department for the current plan list, since that release is several years old.

What Costs Look Like In The Region

The Terner Center's Terner Center statewide ADU owner survey reports a median of $130,000, or $200 per square foot, for Orange and San Diego Counties together. That survey was published in 2021, so current prices may be higher. See ADU Cost In California for the full table and the caveats.

What To Check At Your Address

• San Diego County is a separate jurisdiction from the city. Find out which one governs your address.
• Ask about local requirements for fire access and brush management if your lot borders open space.
• Ask the Development Services Department whether a pre-approved plan fits your lot.

State Rules That Apply Here

• The review deadlines in Permits And Timeline: 15 business days for a completeness notice and 60 days to approve or deny a complete application.
• No impact fees for an ADU of 750 square feet or less (Government Code section 66311.5).
• No owner occupancy requirement for an ADU (Government Code section 66315).

Before You Hire Anyone

Call or visit the planning counter, and bring your address and a sketch of what you have in mind. Then read Questions To Ask An ADU Builder.