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

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

• Detached ADU: A separate building from the main residence
• Attached ADU: Added onto the main home
• Conversion ADU: Converts part of the existing house or accessory structure (e.g., garage) into an ADU
• Junior ADU (JADU): Up to 500 sq ft, converted from part of the home, may share a bathroom with the main home

• Maximum Size:
  
  • Detached: Up to 800 sq ft by right (can be larger if lot coverage and FAR allow)
  • Attached: Up to 50% of primary dwelling, max 1,200 sq ft.
• Setbacks:
  
  • Minimum 4-foot setbacks from the rear and side property lines
• Height Limits:
  
  • Detached ADUs: Up to 16 ft by right
  • May go up to 18 ft–20 ft if located within ½ mile of major transit or with matching roof pitch to primary home (per 2023 state law)
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • Distance to public transit 
    • Architecturally and historically significant historic district
    • Part of proposed or existing primary residence or accessory structure 
    • On-street parking permit requirements
    • Proximity to car share vehicle

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

• Zoning Compliance Review: Confirm the property is in compliance with the local zoning laws.
• Site Plan and Elevations: Include detailed plans that illustrate the proposed ADU's layout and elevations.
• Architectural Drawings: Submit complete architectural plans explaining design and construction
• Structural Calculations and Engineering: Add engineering reports explaining the structural stability 
• Title 24 Energy Documentation: Include documentation proving compliance with California energy code
• Permit Submission: Submit all documents via the City of Berkeley’s online portal, MGO Connect
  

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

Permit times are usually 2 to 3 months depending on the complexity of the project and workload in the city. Some simple projects can be expedited, whereas those with corrections or requiring additional information may take longer. Having experts familiar with Berkeley's ADU process can help make approval easier.

Accessory dwelling units are permitted in any district allowing residential use. Junior ADUs are permitted in single-family zoning districts within an existing single-family residence or as part of a proposed single-family residence. 

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