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

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

• Detached ADU: A standalone structure, such as a backyard cottage or a unit above a garage.
• Attached ADU: A unit connected to the primary home, such as a converted basement, attic, or home addition.
• Conversion ADU: Converted from a garage, basement, or internal space.
• Junior ADU (JADU): Up to 500 sq ft, carved out of existing space within the home.

• Maximum Size:
  
  • Detached: Up to 1,200 square feet
  • Attached: An attached ADU that is created on a lot with an existing primary residence is further limited to 50% of the floor area of the existing primary residence.
• Setbacks:
  
  • Minimum 4 feet from side and rear property lines.
• Height Limits:
  
  • Typically, 16 ft; up to 25 ft for attached ADUs, or the height of the main dwelling (whichever is lower).
    
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • Located within half a mile of a major public transit stop
    • Converted from an existing structure
    • In a historic district or designated area
    • Part of the existing primary residence or an existing accessory structure
    • When on-street parking permits are required but not offered to the occupants of the ADU

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

• Zoning compliance review to determine ADU class (A, B, or C)
• Site plan showing property lines, setbacks, building envelope, lot coverage, and parking
• Architectural and structural drawings prepared by a licensed professional
• Structural calculations and engineering reports as needed
• Energy compliance documentation
• Building permit and, if applicable, ADU permit submission through the City of Lafayette’s online portal
• Utility service applications if separate connections are proposed
  

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

Permit review times in Lafayette vary but are typically between 8 to 12 weeks depending on project complexity and city workload. Projects requiring revisions or corrections may take longer. Engaging professionals familiar with Lafayette’s ADU process can help streamline approval and ensure compliance with zoning and building requirements.

Most single-family residential zones in Lafayette are eligible for ADUs, including RE1, RE2, R1, R2, R3, R4, OTR, and T1 zones. Detached ADUs must generally meet rear and side setback requirements (typically 5 feet) and height limits (16-20 feet depending on the zone). Maximum ADU size is 750 sq. ft., and lot coverage must not exceed 30%. Some special districts, corner lots, or environmentally sensitive areas may have additional restrictions.

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