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

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

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• Detached ADU: The ADU structure is detached from the primary dwelling unit
• Attached ADU: The ADU structure is attached to the primary dwelling unit
• Conversion ADU: The ADU within the existing primary dwelling unit or the ADU was established through the conversion of an accessory structure, for example, a garage or pool house.
• Junior ADU (JADU): Up to 500 sq ft, located within the existing walls of a single-family residence, with certain shared facilities.

• Maximum Size:
  
  • Detached: Up to 1,000 sq ft
  • Attached: Up to 50% of the primary dwelling’s floor area, not exceeding 1,000 sq ft
• Setbacks:
  
  • Minimum 4 ft from side and rear property lines
• Height Limits:
  
  • Typically, 16 ft, 18 ft allowed if within half mile walking distance of high quality transit or major transit stop
• Parking Requirements:
  
  • Additional parking is not required if the ADU is:
    
    • The ADU is within one-half (1/2) mile walking distance of a public transit station, such as a bus stop or train station. 
    • The ADU is created as a result of the conversion of existing area of the single-family residence, accessory structure, garage, or carport.
    • The property is within an architecturally and historically significant historic district.
    • On-street parking permits are required in the area but not offered to the occupant of the residential accessory dwelling unit
    • A car share vehicle is located within one (1) block of the ADU.

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

• Compliance with applicable California building, fire, mechanical, plumbing, electrical, and green building codes
• Site plan showing lot lines, setbacks, existing and proposed structures
• Architectural drawings (floor plans, elevations)
• Structural calculations and engineering details
• Energy compliance per Title 24 (California energy codes)
• Permit submission through the City of Gilroy’s online portal
  

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

Permitting times are variable but usually range between 4 and 6 weeks for typical ADU projects, depending on complexity of project and city workloads. Pre-approved plans for ADU may be expedited to about 2 to 3 weeks. More time may be needed for projects that need corrections or further review. Hiring professionals familiar with Gilroy's ADU process can facilitate processing.

Most residential zones in Gilroy are eligible for ADUs, including single-family, duplex, and multifamily zones. There are no minimum lot sizes for ADUs in most areas of Gilroy. Some hillside, environmentally sensitive, or historic zones may have special restrictions or additional review requirements.

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