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Gilroy ADU Zoning and Building Standards

Building an Accessory Dwelling Unit (ADU) in Gilroy is an excellent way to enhance your property value and accommodate additional living space. Understanding the local zoning and building standards is crucial to ensure a smooth construction process. ADUs provide flexibility, allowing for additional housing options for family members or rental income, and help address the housing shortage in California.

We specialize in guiding homeowners through the ADU building process in Gilroy. Our expertise ensures compliance with local regulations, from initial planning to final construction, making your ADU journey hassle-free and efficient. Our team offers comprehensive services, including site assessment, design, permit application, and construction management, to ensure your ADU project meets all regulatory requirements and is completed on time and within budget.

Gilroy ADU Zoning and Building Standards

Property Requirements

ADUs must comply with specific property requirements to be approved in Gilroy. This includes lot size, zoning classification, and compliance with setback rules. Understanding these requirements is the first step in planning your ADU. Proper assessment of your property will help determine the feasibility of your project and guide the design process.

Building Size

The size of your ADU in Gilroy will depend on the zoning of your property and the existing structures. It’s essential to adhere to these guidelines for successful approval. The building size not only affects the layout and design but also impacts the overall cost and functionality of the ADU.

  • Single-Family Zoned Lots:

Single-family zoned lots in Gilroy can accommodate one ADU, subject to specific size and setback requirements to ensure proper spacing and usage. This zoning classification provides an opportunity for homeowners to add additional living space while maintaining the character and aesthetics of the neighborhood.

  • Duplex Family Zoned Lots:

Duplex family zoned lots are allowed to have more flexibility with ADUs. They can typically accommodate one or more ADUs, subject to size and space constraints. This zoning allows for the creation of additional housing units, making it an attractive option for property owners looking to maximize their investment.

  • Multi-Family Zoned Lots :

Multi-family zoned lots in Gilroy can support multiple ADUs, both attached and detached, providing a versatile solution for additional housing. This zoning is ideal for property owners who want to increase the density of their property and provide more rental opportunities.

  • Attached ADUs:

ADUs attached to the main building offer a seamless integration of additional living space. They are often more cost-effective to build and can share utilities with the primary residence.

  • Detached ADUs:

Detached ADUs provide more privacy and can be a standalone structure on the property. They offer greater flexibility in design and use, making them a popular choice for many homeowners.


In Gilroy, ADU regulations often include owner-occupancy requirements. This means either the main residence or the ADU must be occupied by the property owner. This requirement helps maintain the character of residential neighborhoods and ensures that ADUs are used responsibly.

Number Of Units Allowed

The number of ADUs allowed on a property in Gilroy varies by zoning. Single-family lots typically allow one ADU, while multi-family lots can accommodate more. Understanding the number of units allowed is crucial for planning and designing your ADU project.

Gilroy Building Height

The height of ADUs in Gilroy is regulated to maintain the character of neighborhoods and ensure compatibility with existing structures. Height restrictions help preserve the privacy and sunlight access of neighboring properties.

  • Single-family: For single-family homes, the maximum height for an ADU is typically around 20 feet, ensuring it remains subordinate to the primary residence. This height limit helps maintain the residential scale and aesthetic of single-family neighborhoods.
  • Duplex family: Duplex family properties may have slightly higher allowances, but ADUs usually cannot exceed 25 feet in height to maintain uniformity. This allows for two-story ADUs, providing more living space without overwhelming the surrounding properties.
  • Multi-family: Multi-family properties often allow for taller ADUs, up to 30 feet, to accommodate additional units and maximize space. This height allowance supports the development of larger, multi-story ADUs that can provide significant additional housing.

Gilroy Building Size

Building size limitations for ADUs in Gilroy ensure that the units are appropriately scaled to the property and the existing structures. These limitations help maintain the balance between density and livability in residential areas.

  • Single-Family Freedom: Single-family properties can generally build ADUs up to 1,250 square feet, offering ample space for a comfortable living area. This size allows for a variety of layouts, including one or two-bedroom units with full kitchens and bathrooms.
  • Duplex house: Duplex houses can have ADUs that are slightly larger, often up to 1,450 square feet, to accommodate additional family members or renters. This larger size provides flexibility in design and use, making it suitable for various living arrangements.
  • Multi-Family Mix: Multi-family properties can support larger ADUs, up to 1,650 square feet, providing flexibility in design and usage. This allows for the development of spacious, multi-bedroom units that can accommodate larger families or multiple tenants.

Fire Safety Regulations

Fire safety regulations for ADUs in Gilroy are stringent, requiring smoke detectors, fire-resistant materials, and proper egress windows to ensure occupant safety. Compliance with these regulations is crucial for obtaining building permits and ensuring the safety of residents.


Parking requirements for ADUs in Gilroy vary but generally include the provision of one additional parking space per ADU, unless waived under specific conditions. Adequate parking is essential to avoid congestion and maintain the quality of life in residential neighborhoods.

Utility Connections

ADUs in Gilroy must have separate utility connections, including water, sewer, and electricity, to ensure proper functioning and billing. Proper utility connections are essential for the comfort and convenience of ADU occupants.


Setback requirements for ADUs in Gilroy ensure that the units are appropriately distanced from property lines, typically requiring a minimum setback of 5 feet from side and rear property lines. Setbacks help maintain privacy, reduce noise, and ensure sufficient open space around the ADU.

Zoning Regulations

Zoning regulations in Gilroy define where ADUs can be built, with specific guidelines for single-family, duplex, and multi-family zones. Understanding these regulations is essential for planning and designing your ADU project.

Gilroy ADU Zoning Regulations

Single Family

Single-family zones typically allow for one ADU per lot, with specific size and setback requirements to ensure compatibility with the neighborhood. These regulations help maintain the character and aesthetic of single-family neighborhoods.

Duplex Family

Duplex family zones offer more flexibility, often allowing for multiple ADUs, subject to space and design constraints. This zoning provides an opportunity to increase housing density while maintaining the residential feel of the area.


Multi-family zones can accommodate several ADUs, both attached and detached, providing a versatile solution for additional housing. This zoning is ideal for property owners looking to maximize their investment and provide more rental opportunities.

RF Zone Minimum Lot Area in Gilroy

In Gilroy RF Zone, minimum lot sizes range from spacious single-family homes (RF-20) to sprawling estate properties (RF-40), ensuring ample space for your ADU and lifestyle. The minimum lot area requirements help maintain the character and density of different neighborhoods.

  • RF-20: Minimum lot size of 7,500 square feet, ideal for single-family homes. This lot size provides ample space for a primary residence and an ADU.
  • RF-30: Minimum lot size of 10,500 square feet, suitable for larger properties. This lot size allows for more flexibility in the design and placement of ADUs.
  • RF-40: Minimum lot size of 15,000 square feet, perfect for estate properties. This generous lot size provides ample space for large ADUs and additional outdoor amenities.

Room Specifications Table

Room specifications for ADUs in Gilroy ensure that each unit is functional and meets local building standards. Proper room specifications enhance the livability and functionality of ADUs.

Gilroy ADU Room Specifications

Room TypeSpecifications
Bathroom– Minimum size: 35 sq. ft.
– Ventilation required
– Waterproof flooring
– Accessibility features
– Shower/bathtub combination
Kitchen– Minimum size: 70 sq. ft.
– Counter space: 10 linear feet
– Appliance space: 4 units
– Ventilation hood
– Storage cabinets
Sleeping Areas– Minimum size: 100 sq. ft.
– Egress window
– Closet space: 6 sq. ft.
– Electrical outlets
– Smoke detector
Storage– Minimum size: 25 sq. ft.
– Shelving units: 3
– Secure locking system
– Waterproofing for basement storage
– Accessible location

Gilroy Requirements

Specific requirements for building ADUs in Gilroy include adherence to local zoning laws, building codes, and safety standards. Understanding these requirements is essential for a successful ADU project.

Detached ADU Gilroy: Detached ADUs in Gilroy must comply with zoning regulations, including size limitations and setback requirements, to ensure proper placement and integration into the property. Detached ADUs offer flexibility in design and use, making them a popular choice for homeowners.

Attached ADU Gilroy: Attached ADUs must blend seamlessly with the existing structure, maintaining the architectural style and adhering to size and height restrictions. These units are often more cost-effective to build and can share utilities with the primary residence.

JADU Gilroy: Junior ADUs (JADUs) are smaller units within the existing home, typically limited to 550 square feet, offering an affordable and efficient housing solution. JADUs are a great option for homeowners looking to add a small rental unit or guest suite without significant construction.

Rental Requirements

Renting out your ADU in Gilroy requires adherence to specific guidelines to ensure compliance with local laws and tenant safety. These requirements help protect both the landlord and the tenant.

  • Proof of Income: Prospective tenants must provide proof of income to demonstrate their ability to pay rent. This may include pay stubs, tax returns, or bank statements.
  • Credit Score: A minimum credit score is often required to ensure financial responsibility. A good credit score indicates a history of responsible financial behavior.
  • Rental History: Previous rental history helps gauge the reliability of tenants. References from past landlords can provide insight into a tenant’s behavior and reliability.
  • Application Fee: A non-refundable application fee is typically required. This fee covers the cost of background and credit checks.
  • Security Deposit: A security deposit equivalent to one month’s rent is usually needed. This deposit provides financial security for the landlord in case of damages or unpaid rent.
  • Proof of Renter’s Insurance: Tenants must have renter’s insurance to protect their belongings. This insurance also provides liability coverage in case of accidents.
  • Pet Policy: Specific guidelines on pet ownership, including size and breed restrictions. Pet policies help protect the property and ensure a safe environment for all tenants.
  • Smoking Policy: Clear rules regarding smoking within the ADU to maintain a healthy living environment. Smoking policies help protect the property from damage and ensure a safe environment for all occupants.

Development Standards for Gilroy ADU in Table Form

Development standards for ADUs in Gilroy vary based on the type of property and zoning regulations. These standards ensure that ADUs are built safely and in accordance with local laws.

ADU TypesDevelopment Standards Specifications
Single-family– Max size: 1,250 sq. ft.
– Height limit: 20 feet
– Setback: 5 feet from property lines
– Parking: 1 additional space
– Owner-occupancy requirement
Duplex– Max size: 1,450 sq. ft.
– Height limit: 25 feet
– Setback: 6 feet from property lines
– Parking: 2 additional spaces
– Owner-occupancy requirement
Multi-family– Max size: 1,650 sq. ft.
– Height limit: 30 feet
– Setback: 7 feet from property lines
– Parking: 3 additional spaces
– Owner-occupancy requirement
Junior ADUs (JADUs)– Max size: 550 sq. ft.
– Height limit: 15 feet
– Setback: 4 feet from property lines
– Parking: 1 additional space
– Owner-occupancy requirement

Gilroy Property Designations for ADU

Certain property designations in Gilroy may impact the feasibility of building an ADU, including flood zones, geohazard zones, and easements. Understanding these designations is crucial for planning and designing your ADU.

  • Flood Zones: Properties in flood zones may require additional engineering and safety measures to ensure compliance. These measures may include elevated foundations and flood-resistant materials.
  • Geohazard Zones: Areas prone to geological hazards, such as landslides, may have stricter building codes. Engineering assessments may be required to ensure the stability and safety of the ADU.
  • Easements: Properties with easements must ensure that ADUs do not encroach on these designated areas. Easements may include utility lines, access roads, or conservation areas.

ADU Permit Requirements and Fees

Obtaining the necessary permits is a crucial step in the ADU building process in Gilroy. Various permits are required to ensure compliance with local regulations.

Gilroy ADU Permit Requirements and Fees

  • Building Permit: Required for structural changes and new construction. The building permit process includes plan review and inspections to ensure compliance with building codes.
  • Electrical Permit: Necessary for any electrical work associated with the ADU. This includes wiring, outlets, and electrical panels.
  • Plumbing Permit: Required for plumbing installations and modifications. This includes water supply lines, drainage systems, and fixtures.
  • Other Permits: Additional permits may be needed depending on the scope of the project, such as mechanical or grading permits. These permits ensure that all aspects of the construction meet local codes and standards.

Design Your Dream ADU Today!

Building an ADU in Gilroy is a fantastic way to enhance your property and provide additional living space. With careful planning and adherence to local regulations, your dream ADU can become a reality. Our team is here to guide you through every step of the process, from initial design to final construction. Contact us today to start your ADU project in Gilroy!


Yes, but specific setbacks and design considerations apply. Contact the Woodside Planning Department for detailed guidance on navigating unique lot shapes.

Some lenders offer ADU loans, but traditional home loans can also be used for ADU construction, especially if they add value to your property.

Yes! The State of California offers various ADU incentive programs, including grants for low-income homeowners and developers. Research state and local programs to see if you qualify for financial assistance.

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