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

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

• Detached ADU: are located in free-standing buildings that are separate from the main single-family home or multi-family building
• Attached ADU: involve adding on to a single-family home.
• Conversion ADU: are constructed by converting part of an existing single-family or multi-family home, or by converting all or part of an accessory building (like a garage, shed, or studio). This includes garage conversions.
• Junior ADU (JADU): involve converting part of the single-family home into a new dwelling unit that’s no more than 500 square feet and that may share a bathroom with the main home.

• Maximum Size:
  
  • Detached: Up to 1,200 sq ft
  • Attached: 50% of existing home. Inside existing home
• Setbacks:
  
  • Minimum 4’ side and rear yard setback.
• Height Limits:
  
  • ADU is located close to the side or rear property lines (i.e. within setback areas), the maximum height is lower: 16 feet in those zones
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • Located within half a mile of public transit
    • Converted from an existing garage or accessory structure
    • In a historic district or designated area
    • In an area where on-street parking permits are required but not offered to ADU occupants
    • Within one block of a car-share vehicle

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

• Planning review and approval from the City of Orinda
• Site plan showing property lines, setbacks, and location of the ADU
• Architectural drawings (floor plans, elevations, sections, details)
• Structural calculations and engineering, if applicable
• Title 24 energy compliance documentation
• Fire safety compliance (if in a high fire hazard zone)
• Building permit submission through Contra Costa County’s permitting system
• Use of pre-approved ADU plans is allowed, but still requires site-specific review and permits
  

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

Permit review times vary but are typically between 2 to 6 months depending on project complexity, completeness of plans, and city/county workload. Projects requiring corrections or additional review may take longer. Engaging professionals familiar with Orinda’s ADU permitting process can help streamline approval.

Most residential zones in Orinda are eligible for ADUs, including single-family residential districts. There are no minimum lot size requirements for ADUs. Detached and attached ADUs must meet setback and height standards, while conversion ADUs have more flexibility. Some hillside or high fire hazard zones may have additional restrictions.

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