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Fremont ADU Zoning and Building Standards

Whether you’re planning to build an Accessory Dwelling Unit (ADU) for extra income, housing a family member, or increasing property value, this guide provides everything you need to know. Our team of experts is dedicated to assisting you through every step of your ADU project in Fremont. From initial planning and zoning requirements to final construction, we’re here to ensure your ADU meets all local standards.

Fremont ADU Zoning and Building Standards

Property Requirements

Property requirements for building an ADU in Fremont ensure safety and compliance with zoning laws. Your lot must meet specific criteria, including minimum size and proper zoning designation, to qualify for an ADU.

Building Size

Building size regulations for ADUs in Fremont vary by property type. Understanding these size limits is crucial for ensuring your ADU project adheres to local building codes and standards.

  • Single-Family Zoned Lots:

Single-family zoned lots in Fremont allow homeowners to add an ADU, provided the unit meets the necessary size and setback requirements. This addition offers a flexible living solution.

  • Duplex Family Zoned Lots:

Duplex family zoned lots permit the construction of ADUs, enhancing the utility of your property by providing additional living space or rental opportunities.

  • Multi-Family Zoned Lots :

Multi-family zoned lots in Fremont can accommodate multiple ADUs, significantly increasing housing options and maximizing property use.

  • Attached ADUs:

Attached ADUs are connected to the main dwelling, sharing a wall or part of the structure, ideal for maintaining a cohesive property design.

  • Detached ADUs:

Detached ADUs are separate structures on the same lot, offering more privacy and flexibility in use compared to attached units.


Fremont requires that either the primary residence or the ADU be owner-occupied. This rule helps maintain neighborhood stability and ensures responsible property management.

Number Of Units Allowed

In Fremont, zoning laws dictate the number of ADUs allowed per lot. Generally, single-family lots can have one ADU, while multi-family lots can have multiple units.

Fremont Building Height

Building height restrictions for ADUs in Fremont are designed to maintain neighborhood aesthetics and prevent overshadowing neighboring properties.

  • Single-family: Single-family ADUs in Fremont have a maximum height limit to ensure they blend well with the existing neighborhood structures and maintain a harmonious look.
  • Duplex family: Duplex family ADUs have specific height restrictions that balance additional living space with maintaining the overall neighborhood character.
  • Multi-family: Multi-family ADUs can be taller but must still comply with local height restrictions to avoid negatively impacting surrounding properties.

Fremont Building Size

Building size regulations for ADUs in Fremont vary based on the type of lot and existing structures, ensuring that new units are appropriately scaled.

  • Single-Family Freedom: Single-family properties in Fremont have specific size limits for ADUs, ensuring the new unit complements the primary residence without overwhelming the lot.
  • Duplex house: Duplex houses can add ADUs that enhance property utility without compromising the overall site layout, adhering to size limits for balance and usability.
  • Multi-Family Mix: Multi-family properties can incorporate multiple ADUs, following size guidelines to ensure functionality and aesthetic appeal across the site.

Fire Safety Regulations

ADUs in Fremont must comply with strict fire safety regulations, including accessible exits, smoke detectors, and fire-resistant materials, to ensure occupant safety.


Parking requirements for ADUs in Fremont are designed to manage increased vehicle needs while minimizing impacts on street parking and neighborhood congestion.

Utility Connections

ADUs in Fremont require proper utility connections for water, sewer, electricity, and gas, ensuring the unit is fully functional and compliant with health and safety standards.


Setback regulations in Fremont dictate the minimum distance ADUs must be from property lines, ensuring adequate space and privacy between structures.

Zoning Regulations

Zoning regulations for ADUs in Fremont ensure that new units are compatible with existing neighborhood characteristics and land use patterns.

Fremont ADU Zoning Regulations

Single Family

Single-family zoning regulations in Fremont allow for ADUs, provided they meet specific criteria related to size, height, and setbacks, ensuring they fit the neighborhood.

Duplex Family

Duplex family zoning permits ADUs, enhancing property utility and providing additional housing options while maintaining community standards.


Multi-family zoning allows for multiple ADUs, maximizing the property’s housing potential and supporting diverse living arrangements within the regulations.

RF Zone Minimum Lot Area in Fremont

In Fremont’s RF Zone, minimum lot sizes vary, ensuring ample space for ADUs and maintaining the area’s residential character.

  • RF-20: The RF-20 zone in Fremont requires a minimum lot size, providing space for single-family homes with room for an ADU, ensuring spacious and comfortable living arrangements.
  • RF-30: RF-30 zoning in Fremont sets larger minimum lot sizes, accommodating more extensive properties and allowing for significant ADU additions, enhancing living space options.
  • RF-40: In the RF-40 zone, Fremont’s most extensive lots provide ample room for substantial ADUs, perfect for estate properties seeking additional housing units.

Room Specifications Table

Room specifications for ADUs ensure each space meets essential requirements for functionality and comfort. Below is a detailed table:

Fremont ADU Room Specifications

Room TypeSpecifications
Bathroom– Minimum size: 70 sq. ft
– Ventilation: Exhaust fan required
– Fixtures: Sink, toilet, shower/tub
– Flooring: Waterproof material
– Lighting: Overhead and vanity lights
Kitchen– Minimum size: 120 sq. ft
– Appliances: Stove, refrigerator
– Counter space: 30 linear feet
– Storage: Upper and lower cabinets
– Sink: Double-basin
Sleeping Areas– Minimum size: 150 sq. ft
– Egress: Window or door required
– Closet: Built-in or wardrobe
– Lighting: Overhead and bedside
– Flooring: Carpeting or hardwood
Storage– Minimum size: 50 sq. ft
– Shelving: Adjustable or fixed
– Accessibility: Easy access points
– Security: Lockable doors
– Ventilation: Adequate airflow

Fremont Requirements

Understanding Fremont’s specific requirements for ADUs ensures your project complies with all local regulations, from design to construction.

Detached ADU Fremont: Detached ADUs in Fremont must adhere to size, height, and setback regulations, ensuring they fit well within the neighborhood context and provide additional living space.

Attached ADU Fremont : Attached ADUs share a wall with the main dwelling, requiring careful planning to meet structural and design standards, while seamlessly integrating with the existing home.

JADU Fremont : Junior ADUs (JADUs) in Fremont are smaller units within the primary dwelling, typically converted from existing space, and must meet specific guidelines for functionality and safety.

Rental Requirements

Renting out your ADU in Fremont involves meeting several requirements to ensure the unit is suitable for tenants and complies with local regulations.

  • Proof of income: Tenants must provide proof of income to demonstrate their ability to pay rent, ensuring a reliable rental arrangement.
  • Credit score: A good credit score is required for tenants to assess their financial responsibility and ability to manage rental payments.
  • Rental history: Prospective tenants should have a solid rental history, showcasing their reliability and previous experiences with rental properties.
  • Application fee: An application fee covers the cost of processing tenant applications, including background and credit checks, ensuring thorough vetting.
  • Security deposit: A security deposit is required to cover potential damages or unpaid rent, providing financial protection for property owners.
  • Proof of renter’s insurance: Tenants must provide proof of renter’s insurance, safeguarding their belongings and offering liability protection.
  • Pet policy: The pet policy outlines whether pets are allowed in the ADU, including any restrictions or additional deposits required.
  • Smoking policy: A clear smoking policy helps maintain a healthy living environment, specifying whether smoking is permitted inside the ADU.

Development Standards for Fremont ADU in Table Form

Development standards for ADUs in Fremont ensure each unit is built to meet specific criteria for safety, functionality, and design.

ADU TypesDevelopment Standards Specifications
Single-family– Max size: 850 sq. ft
– Height: 17 ft
– Setbacks: 5 ft sides, 10 ft rear
– Parking: 1 space required
– Owner occupancy: Required
Duplex– Max size: 950 sq. ft
– Height: 18 ft
– Setbacks: 5 ft sides, 10 ft rear
– Parking: 1 space required
– Owner occupancy: Required
Multi-family– Max size: 1050 sq. ft
– Height: 20 ft
– Setbacks: 5 ft sides, 10 ft rear
– Parking: 1 space required per unit
– Owner occupancy: Required
Junior ADUs (JADUs)– Max size: 500 sq. ft
– Height: Same as main dwelling
– Setbacks: Not applicable
– Parking: Not required
– Owner occupancy: Required

Fremont Property Designations for ADU

Property designations impact where ADUs can be built in Fremont, ensuring they are located in safe, suitable areas.

  • Flood zones: ADUs in flood zones require additional precautions and approvals to ensure they are safe from potential water damage.
  • Geohazard zones: Building in geohazard zones involves extra engineering and safety measures to protect against natural risks like earthquakes or landslides.
  • Easements: Properties with easements must consider these when planning ADUs, ensuring access and utility rights are maintained.

ADU Permit Requirements and Fees

Obtaining the necessary permits is crucial for ADU construction in Fremont, ensuring compliance with all local building codes and regulations.

Fremont ADU Permit Requirements and Fees

  • Building Permit: A building permit is required for any new ADU construction or significant modifications to existing structures, ensuring safety and compliance.
  • Electrical Permit: An electrical permit is necessary for any electrical work in the ADU, guaranteeing it meets safety standards and is properly installed.
  • Plumbing Permit: Plumbing permits ensure all water and sewer connections in the ADU are up to code, providing safe and reliable utilities.
  • Other Permits: Additional permits may be required for specific aspects of ADU construction, such as mechanical or gas line work, ensuring comprehensive compliance.

Design Your Dream ADU Today!

Start designing your dream ADU in Fremont today with our expert guidance and support. We’ll help you navigate the zoning, permitting, and building process to create the perfect space.


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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