ADUCheckby ViviendaCheck a propertyCheck

ADUs in San Diego: rules, requirements and what fits on your property

What state law allows on any property in San Diego, what the city adds, and what it costs to build. Updated November 6, 2026.

The typical home in San Diego is worth about $980,490 and rents for about $3,004 a month (Zillow, September 2026). An ADU adds a second home to that property under the rules below.

Report with the parcel, the home outline, the space for a detached ADU and the fire zone from San Diego County's GIS, under the state rules.

What state law allows in San Diego

These apply in every California city and county. The city can allow more, never less. State rules current to November 6, 2026.

  • Detached ADU

    Up to 1,200 sq ft. At least 800 sq ft is always allowed.

  • Height

    16 ft; 18 ft within half a mile of transit, plus 2 ft for a roof that matches the home.

  • Setbacks

    4 ft from the side and back of the property.

  • Parking

    None needed within half a mile of transit, or for a conversion.

  • Fees

    No impact fees up to 750 sq ft. No school fees up to 500 sq ft.

  • Timeline

    The city must decide within 60 days of a complete application.

What San Diego adds

From the city's zoning code and ADU handbook. These join reports when San Diego is covered.

ADU handbook
ADU and JADU page, with Information Bulletin 400Read November 6, 2026.
Pre-approved plans
Accepts preapproved plans under AB 1332 from the County of San Diego, Chula Vista and EncinitasRead November 6, 2026.
Homeowner associations
HOAs can set reasonable rules but can’t ban ADUs (Civil Code 4751).

San Diego in numbers

Figures from public sources, each with where it was read and when.

Typical home value
$980,490Zillow Home Value Index, mid-tier, September 2026. Read November 7, 2026.
Typical rent
$3,004 a monthZillow Observed Rent Index, all homes, September 2026. Read November 7, 2026.

Questions about ADUs in San Diego

Short answers from the state rules and the city's own figures. Your address gives the answer for your property.

Can I build an ADU in San Diego?
Yes. State law requires every California city and county, including San Diego, to allow at least one ADU on a property with a home, and a junior ADU inside the home. Most properties zoned for homes qualify. San Diego can add its own limits but cannot go below the state minimums. Enter your address to see the rules for your property.
How big can an ADU be in San Diego?
State law allows a detached ADU of up to 1,200 sq ft, and at least 800 sq ft is always allowed regardless of lot coverage. A junior ADU inside the home can be up to 500 sq ft. An attached ADU can be half the size of the home, and 800 sq ft is always allowed.
What are the setback and height rules for an ADU in San Diego?
At least 4 ft from the side and back of the property. Height is 16 ft, or 18 ft within half a mile of major transit, plus 2 ft for a roof that matches the home. San Diego can allow more.
Do I need parking for an ADU in San Diego?
No parking is required within half a mile of major transit, for a garage conversion, or when parking is available on the street. When a garage is converted, no replacement parking is required.
How much does an ADU cost in San Diego?
Build cost depends on size and the site. ADUCheck's range is $250 to $400 per sq ft for new construction and $100 to $200 per sq ft for a conversion, from the Terner Center ADU owner survey. The typical home in San Diego is worth about $980,490 (Zillow, September 2026). City impact fees are waived up to 750 sq ft and school fees up to 500 sq ft.
What does an ADU rent for in San Diego?
The typical home in San Diego rents for about $3,004 a month (Zillow Observed Rent Index, September 2026). A new one- or two-bedroom ADU usually rents for less than a full home in the same ZIP.
Does San Diego have pre-approved ADU plans?
Yes. Accepts preapproved plans under AB 1332 from the County of San Diego, Chula Vista and Encinitas (read from the city's own page on November 6, 2026).
How long does an ADU permit take in San Diego?
State law gives the city 15 business days to say whether your application is complete and 60 days from a complete application to approve or deny it. A missed deadline counts as approval.

Other cities in San Diego County

Every city in San Diego County