The City of San Ramon permits ADUs across most residential zones. San Ramon 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 Ramon aligns with California’s broader ADU legislation but has its own requirements for height, setbacks, and design review.

• Detached ADU: A standalone unit located on the same lot as the primary residence.
• Attached ADU: A unit that shares a wall with the primary residence but has its own separate entrance.
• Conversion ADU: Created by converting an existing structure, such as a garage, attic, or basement, into a livable unit. 
• Junior ADU (JADU): unit not exceeding 500 square feet, created entirely within an existing single-family structure. It may share sanitation facilities with the main home or include separate facilities

• Maximum Size:
  
  • Detached: Up to 1,200 sq ft
  • Attached: Up to 50% of the existing dwelling's net floor area, up to 1,200 sq ft.
• Setbacks:
  
  • Minimum 4 ft from side and rear property lines
• Height Limits:
  
  • Typically, 16 ft, Height based on maximum allowed in the applicable residential zone. 
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • Located within ½ mile of public transit
    • Converted from an existing structure (e.g., garage, basement, or other accessory building)
    •  Located in a historic district or other designated area with special standards

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

• Zoning compliance review to ensure the ADU meets local zoning standards
• Site plan and elevations showing the property layout and proposed ADU.
• Architectural drawings including floor plans, sections, and elevations.
• Structural calculations and engineering for foundation, framing, and load-bearing elements
• Title 24 energy compliance documentation to meet California energy efficiency standards
• Permit submission through the City of San Ramon’s Planning Services Division
  

Homeowners should also review San Ramon’s current fee schedule, utility connection requirements, fire code compliance, and ensure any required deed restrictions (e.g., prohibiting short-term rentals) are recorded before final inspection.

Permit review times in San Ramon typically range from 6 to 12 weeks, depending on project complexity and City workload. Projects requiring corrections or plan revisions may take longer. Engaging professionals familiar with San Ramon’s ADU process can help streamline approval and reduce delays.

Most residential zones in San Ramon are eligible for ADUs, including single-family residential (R-1) and other designated residential zones. A primary dwelling must exist or be proposed on the lot. There are generally no minimum lot size requirements for ADUs in most areas, though some hillside, environmentally sensitive, or special overlay zones may have additional restrictions regarding setbacks, height, or design.

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