The City of Cupertino permits ADUs across most residential zones. Cupertino 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.

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

• Detached ADU: A standalone unit in the backyard, up to 1,200 sq ft, 18 ft height, minimum 4 ft setbacks
• Attached ADU: A unit attached to the main home, up to 50% of the primary dwelling or 1,000 sq ft, height up to 25 ft or same as primary dwelling
• Conversion ADU: Converted from a garage, basement, or attic space, must meet building codes
• Junior ADU (JADU): Up to 500 sq ft, carved out of existing space within the home, must include an efficiency kitchen

• Maximum Size:
  
  • Detached: Up to 1,200 sq ft
  • Attached: Up to 50% of the primary dwelling’s floor area, not exceeding 1,000–1,200 sq ft
• Setbacks:
  
  • Minimum 4 ft from side and rear property lines
• Height Limits:
  
  • Typically 18 ft, up to 25 ft depending on location and unit type
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • Within ½ mile of public transit
    • Converted from an existing structure
    • In a historic  or designated area

To build an ADU in Cupertino, the following approvals are typically required:

• Zoning compliance review
• Site plan and elevations
• Architectural drawings
• Structural calculations and engineering
• Title 24 energy documentation
• Permit submission through the City of Cupertino’s online portal
  

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

Typically 6–12 weeks, depending on complexity and city workload.

Most residential zones are eligible for ADUs, including R-1, RHS, A, and A-1 zones. There are no minimum lot sizes for ADUs in most areas of Cupertino. Some hillside or environmentally sensitive zones may have special restrictions.

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