Single-dwelling ADU combinations
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.
California ADU rules · popularity rank #2
San Diego ADU Rules & Requirements
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.
Quick facts
- 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
Detached ADU size
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.
Caveat-aware review
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.
Check these rules against your lot
City rules explain the ceiling. Your parcel determines the practical answer: zoning, lot size, APN, setbacks, overlays, and buildable area.
Check my propertyTop California ADU city rules
San Diego ADU FAQ
No. These pages summarize official city and state rule sources for planning research. Permit approval still depends on parcel geometry, zoning details, overlays, easements, fire access, utilities, and plan-check review.
California ADU law creates statewide minimum paths, while cities keep local standards for many project types. Showing both paths keeps the homeowner from treating a single city rule as the whole answer.
Run an address-specific feasibility check. The report combines official city rules with deterministic GIS and parcel data so the next question becomes what fits on your actual lot.
Source notes
Summaries reflect the official source listed below 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.
Information Bulletin 400 - Accessory Dwelling Unit/Junior Accessory Dwelling UnitCanonical URL: https://homefeasible.com/city/san-diego/adu