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

Hayward 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 (Hayward allows detached ADUs up to 1,200 sq ft)
• Attached ADU: Added onto the main home (attached ADUs are permitted per Hayward’s definition)
• Conversion ADU: Converts part of existing structure (e.g., garage) into ADU (Hayward allows conversion ADUs of existing permitted structures)
• Junior ADU (JADU): Up to 500 sq ft, converted from part of the home, may share a bathroom with the main home (Hayward allows JADUs with ≤ 500 sf, internal conversion, efficiency kitchen, may share bathroom)

• Maximum Size:
  
  • Detached: Hayward allows up to 1,200 sq ft for new ADU construction (subject to lot conditions)
  • Attached: Up to 50% of the primary dwelling, with a maximum of 1,200 sq ft
• Setbacks:
  
  • Minimum 4-foot setbacks from the rear and side property lines
• Height Limits:
  
  • Detached ADUs: typically limited to 16 feet in height
  • Attached ADUs: must not exceed height limits applicable to primary structure (varies by zone)
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • A conversion ADU (i.e., using existing interior space) or an ADU
    • Located within ½ mile of public transit
    • Situated within a historic district
    • Within one block of a car-share service

To build an ADU or JADU in Hayward, the following approvals are typically required:

• Zoning Compliance Review: Confirm the property is in compliance with local zoning laws
• Site Plan and Elevations: Include detailed plans illustrating the proposed ADU's layout and elevations
• Architectural Drawings: Submit complete architectural plans explaining the design and construction
• Structural Calculations and Engineering: Provide 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 Hayward's online portal, MGO Connect
  

Homeowners should also review Hayward’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 Hayward's ADU process can help make approval easier.

Accessory dwelling units shall be a permitted use in any district where residential uses are permitted. Junior accessory dwelling units shall be permitted in the 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 Hayward.