ADU feasibility · San Diego, CA

ADU feasibility in San Diego: rules, bonus program, costs & rents (2026)

Q: How big can a San Diego ADU be?

Detached ADUs are limited to 1,200 sq ft and two stories. Units up to 800 sq ft are exempt from lot-coverage limits, and units under 750 sq ft are exempt from development impact fees.

Q: Can I sell a San Diego ADU separately?

Yes — San Diego has adopted AB 1033, which allows an ADU to be converted to a condominium and sold separately from the main home, subject to the city's process.

Updated June 2026 · Rules current as of the 2026 California ADU framework

San Diego has been one of California's most active ADU markets — by 2024 nearly one in five new homes in the city was an ADU. The 2026 rules, plus the city's ADU Bonus Program, decide what you can build. Here's the framework, typical costs and rents, and how to check your specific lot.

San Diego ADU rules at a glance (2026)

Max detached ADU: 1,200 sq ft · 2 stories
Side / rear setback: 4 ft
Owner-occupancy: Not required*
Parking: Waived in transit areas
By-right units: 1 ADU + 1 JADU
Impact fees: Waived under 750 sf

San Diego follows California's statewide ADU framework and adds local detail through its Land Development Code. * Standard ADUs carry no state owner-occupancy requirement; junior ADUs sharing sanitation with the main house are the exception — confirm current status with the city's Planning Department.

The San Diego ADU Bonus Program

San Diego's Bonus Program lets owners build additional units beyond the state baseline in exchange for deed-restricting one as affordable (10–15 years), with the biggest incentives in transit-rich Sustainable Development Areas. After 2025 reforms, the larger multi-unit pathway is tied to lot size and zoning — most single-family lots are effectively limited to about two units, with bigger projects pushed to larger lots in multi-family zones. If you're building to rent at scale, it's worth modeling; if you're adding one backyard unit, the standard pathway is simpler.

Cost & rent snapshot

Build cost

$150k–$350k

Rent · 1BR

$1,700–$2,400

Rent · 2BR

$2,100–$3,000

Typical 2026 ranges for detached new construction; garage conversions run lower. San Diego rents vary widely by neighborhood — run your address below for site-specific comps rather than relying on a citywide range.

Local tip: Sizing a unit under 750 sq ft skips development impact fees (often $5k+), and units up to 800 sq ft are exempt from lot-coverage limits — useful on a built-out lot. Coastal Overlay Zone properties may also need a Coastal Development Permit.

See what your San Diego lot can actually build.

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Frequently asked questions

How many ADUs can I build in San Diego?

By right, most single-family lots allow one detached ADU plus one junior ADU. The ADU Bonus Program can add more if you deed-restrict an affordable unit, but 2025 reforms tied the larger multi-unit pathway to lot size and zoning.

How big can a San Diego ADU be?

Detached ADUs are capped at 1,200 sq ft and two stories. Units up to 800 sq ft are exempt from lot-coverage limits; units under 750 sq ft skip development impact fees.

Can I sell a San Diego ADU separately?

Yes — San Diego adopted AB 1033, which allows converting an ADU to a condominium and selling it separately from the main home, through the city's process.

Is parking required?

Parking is generally waived in Transit Priority Areas; outside them, standards may apply. Garage conversions never require replacing the lost spaces.

Sources: City of San Diego Development Services Department (ADU/JADU program, ADU Home Density Bonus Program); California HCD ADU Handbook (2026 update); UC Berkeley Terner Center ADU research. Rules summarized for general guidance and current as of June 2026 — ADU law changes frequently and your lot's specifics govern. Verify with the City of San Diego before designing or contracting.