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

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

• Detached ADU: Separate building from the main residence with independent living facilities.
• Attached ADU: An ADU that is attached to the primary residence, but functions as a standalone living unit
• Conversion ADU: Converts a portion of an existing dwelling or accessory structure
• Junior ADU (JADU): Up to 500 sq ft, converted from part of the home, may have its own bathroom or share one with the existing structure, and includes an efficiency kitchen

• Maximum Size:
  
  • Detached: Up to 1,000sq ft 
  • 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: maximum height 16 feet
  • Attached: 30 feet Or the building height of the underlying zoning district, whichever is lower       
• Parking Requirements:
  
  •  No additional parking is required if the ADU is:
    
    • A 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 Fremont, 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 the design and construction.
• Structural Calculations and Engineering: Add engineering reports explaining the structural stability of the ADU.
• Title 24 Energy Documentation: Include documentation proving the property complies with California's energy efficiency code
• Permit Submission: All necessary documents should be submitted via the City of Fremont's online portal, MGO Connect
  

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

Permit times are usually 6 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 Fremont's ADU process can help make approval easier.

Accessory dwelling units (ADUs) are permitted in all residential zoning districts. Junior accessory dwelling units (JADUs) are allowed within existing single-family residences or as part of a proposed single-family residence.

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