The City of San Jose permits ADUs across most residential zones. San Jose follows both state and local ADU laws, allowing most single-family homes to build one detached ADU and one Junior ADU (JADU) per lot. Multi-family properties may be eligible for multiple ADUs, depending on site conditions.

San Jose aligns with California’s broader ADU legislation but has its own requirements for height, setbacks, and design review.

• Detached ADU: A separate unit, either newly built or converted, located behind the main home
• Attached ADU: A unit attached to the main residence
• Conversion ADU: Created by converting existing space such as a garage, basement, or other internal area
• Junior ADU (JADU): Up to 500 sq ft, built within the existing single-family home footprint, including conversion of an attached garage; requires owner occupancy of the main home

• Maximum Size:
  
  • Detached: Up to 1,200 sq ft
  • Attached: Up to 50% of the primary dwelling’s floor area, not exceeding 1,200 sq ft
• Setbacks:
  
  • Minimum 4 ft from side and rear property lines
• Height Limits:
  
  • Detached ADU: 18 ft for single story; up to 25 ft for two stories
  • Attached ADUs: Up to 25 ft
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • Lots >9,000 sf max ADU size 1,200 sf, or Lots <9,000 sf, max ADU size 1,000 sf

To build an ADU in San Jose, applicants must complete:

• Property qualification and designation checks using SJPermits.org
• Compliance with zoning, building, and fire codes
• Fire safety review by the City’s Fire Prevention Bureau
• Site plan and vicinity map
• Fire hydrant distance and flow verification
• Pool demolition or geotechnical documents (if applicable)
  

Homeowners should also review San Jose’s current fee schedule, utility connection requirements, and fire code compliance.

The checklist does not specify review timeframes. However, timely processing depends on submission completeness - delays commonly occur when applicants fail to provide required documentation, such as the water flow letter or code compliance clearance.

ADUs are permitted in zoning districts with a legally built main residence (single-family, duplex, or multifamily). No ADUs are allowed on properties with unpermitted main homes or unresolved code violations. Special conditions apply for properties in flood, seismic, historic, or Wildland-Urban Interface zones. Construction must comply with easement restrictions and nonbuildable area limitations (e.g., demolished pools).

For the most current and complete information, refer directly to the City of San Jose.