California ADU rules - popularity rank #2
San Diego ADU rules are organized around city standards in Information Bulletin 400, including detached ADUs, conversion ADUs, JADUs, and multifamily paths. Some setbacks and fire-area cases depend on the lot and building code review.
Based on 4 curated rule paths from official sources. Last reviewed June 2026. Use this page as the rule starting point, then run the address check to see which path matches your lot.
Popularity rank
#2 California ADU market
Rule paths
4 curated ADU rule sets
Detached max size
1,200 sq ft
Minimum unit size
150 sq ft
Parking
Often waived by exemption
Primary source
San Diego IB 400
Rule snapshot
These sections mirror the questions homeowners search for: size, setbacks, parking, permit workflow, and which ADU type is available. The rows stay source-backed and avoid turning a city rule into parcel approval.
Planning a garage conversion ADU?
Read the California garage conversion guide, then run the address check to match the city baseline to the actual lot.
Estimating ADU permit cost?
Permit cost depends on the fee stack, ADU type, size, waivers, and plan-check path for this city.
San Diego's official bulletin organizes single-dwelling and multifamily ADU paths under city standards.
San Diego has homeowner-friendly size rules, but setbacks can depend on fire and building-code review.
Parking and setback answers can change in Coastal Overlay and very high fire hazard severity zones.
Why this is a starting point
Competitor rule pages often stop at a city summary. The useful next step is matching those rules to an actual lot, because zoning, parcel geometry, overlays, and selected ADU type decide what a homeowner should do next.
San Diego's city standards allow a single-dwelling lot to combine attached or detached ADU options with conversion and JADU paths where the official criteria are met.
The curated detached path shows a 150 sq ft minimum and 1,200 sq ft maximum, with front-setback and side/rear-yard details depending on placement and code constraints.
Very high fire hazard severity zone cases and building/fire-code details can change the practical answer, so the page keeps these as source-backed caveats instead of approval claims.
Free ADU Check
The city page gets the search visitor in the door. The ADU Check turns the visit into a property-specific report path.
Start free address checkThe check matches the typed address to jurisdiction, zoning, parcel context, and the closest stored ADU rule path.
Detached, attached, conversion, garage conversion, and JADU paths are handled separately when the city source supports them.
The report keeps official rule text separate from parcel-specific caveats, so a homeowner can see the rule and the remaining risk.
Official links
These are outbound official sources from HomeFeasible's reviewed ADU rule collection. They are here for verification and trust; the address check is the next step for a property-specific answer.
Internal links
Top questions
Summaries reflect official source links and the structured ADU rule data collected for HomeFeasible's first launch. Regulations change and individual parcels vary; verify current requirements with the city planning department or run a parcel-specific check before making decisions.
Canonical URL: https://homefeasible.com/city/san-diego/adu
