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

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

• Detached ADU: A self-contained unit positioned away from the primary home, usually in the backyard
• Attached ADU: A unit physically connected to the main home
• Conversion ADU: Converted from an existing garage into a living space
• Junior ADU (JADU): is a unit up to 500 square feet and converted from any existing floor space including (but not limited to) a basement, or garage

• Maximum Size:
  
  • Detached: ADU not exceeding 800 square feet
  • Attached: Up to 50% of the primary dwelling’s floor area, not exceeding 1,200 sq ft
• Setbacks:
  
  • Detached: 4 ft from side and rear property lines
  • Attached: 4 ft from side and rear property lines
• Height Limits:
  
  • Detached: 16 feet, 24 feet if the ADU meets the same setbacks applicable to the primary residence
  • Attached: 25 feet or the same height allowed for the primary residence if the unit meets the setbacks applicable to the primary residence
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • The ADU is located within one-half mile walking distance of public transit
    • The ADU is located within an architecturally and historically significant historic district
    • The ADU is part of the proposed or existing primary residence or an accessory structure
    • When on-street parking permits are required, but not offered to the occupant of the Accessory Dwelling Unit

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

• Zoning compliance review: Ensures compliance with objective development standards
• Site plan and elevations: Scale drawings required, indicating project data. Planning Commission reviews and approves site plans and elevations
• Architectural drawings: Required for permit application. Include floor plans with interior layout and details on finishes and materials
• Structural calculations and engineering: Responsibility of the homeowner to provide; not included in some pre-designed ADU plan services
• Title 24 energy documentation: verifies compliance with California Energy Code, includes CF-1R form
• Permit submission: Submit ADU permit applications through the city of Danville permit Center
  

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

Permit review times vary but are typically between 30 days depending on project complexity and city workload. Projects requiring corrections may take longer. Engaging professionals familiar with Danville’s ADU process can help streamline approval.

Most residential zones are eligible for ADUs, including R-1, R-2, and R-3 zones. There are no minimum lot sizes for ADUs in most areas of Danville. Some hillside or environmentally sensitive zones may have special restrictions.

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