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

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

• Detached ADU: Separate new, free-standing structure on your property
• Attached ADU: Added to the primary residence
• Conversion ADU: Conversion of existing space within the primary home or a detached accessory structure
• Junior ADU (JADU): Up to 500 sq ft, conversion of existing space within a single-family home

• Maximum Size:
  
  • Detached: up to 1,200 square feet in ADUs 
  • Attached: Up to 50% of primary dwelling, max 500 sq ft
• Setbacks:
  
  • Minimum 4-foot setbacks from the rear and side property lines
• Height Limits:
  
  • Typically 16 ft unless
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • Conversion ADU or Junior ADU (entirely within the existing primary residence or accessory structure)
    • Located within ½ mile of public transit
    • Situated within a historic district
    • Within one block of a car-share service

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

• Zoning Compliance Review: Confirm that the property complies with Concord’s zoning and development standards for ADUs and JADUs
• Site Plan and Elevations: Submit a detailed site plan showing the proposed ADU’s location, setbacks, and elevations
• Architectural Drawings: Provide full architectural drawings demonstrating the ADU’s floor plan, design, and construction details
• Structural Calculations and Engineering: Include structural and engineering documentation verifying compliance with building safety requirements
• Title 24 Energy Documentation: Include energy compliance documentation showing the ADU meets California’s energy efficiency requirements
• Permit Submission: All required documents should be submitted through the City of Concord’s Building Division either online or in person at City Hall
  

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

Permit times are usually 8 to 12 weeks 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 Concord's ADU process can help make approval easier.

Accessory dwelling units (ADUs) shall be a permitted use in any zoning district where residential uses are allowed. Junior accessory dwelling units (JADUs) shall be permitted within single-family zoning districts, located within an existing or proposed single-family residence, including an attached garage 

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