Introduction
Sunnyvale’s rules and regulations for accessory dwelling units (ADUs) are designed to encourage the development of additional housing while maintaining the city’s aesthetic and structural integrity. The city offers clear guidelines that balance community needs with property owner flexibility. ADU Specialist Bay Area is here to help you navigate these regulations effortlessly, providing expert advice and support from initial planning through to final approval.
Essential ADU Rules for Sunnyvale
What you can build
Maximum size
ADUs can be up to 1,000 square feet.
Side / rear setbacks
Minimum of 4 feet from property lines.
Two stories
Allowed with a maximum height of 16 feet.
Building separation
At least 10 feet from the main dwelling.
Permitting timeline
Standard
Approximately 60 days for standard review.
Coastal
Not applicable to Sunnyvale.
Zoning Regulations in Sunnyvale
ADUs in Sunnyvale must comply with zoning regulations, ensuring they fit within residential zoning areas and meet specific lot requirements.
ADU Size Limitations
| Lot Size | Single-Family (Maximum Floor Area Allowed) | Duplex and Multi-Family (Maximum Floor Area Allowed) |
| Under 7000 | 700 sq ft | Not permitted |
| 7000 - 9999 | 800 sq ft | 1 ADU + 400 sq ft per existing unit (up to 1000 sq ft max) |
| 10000 - 12999 | 900 sq ft | 1 ADU + 450 sq ft per existing unit (up to 1000 sq ft max) |
| 13000 - 19999 | 1000 sq ft | 1 ADU + 500 sq ft per existing unit (up to 1000 sq ft max) |
| 20000+ | 1000 sq ft | 1 ADU + 550 sq ft per existing unit (up to 1000 sq ft max) |
ADU Height Limitations
The height of an ADU in Sunnyvale should not exceed 16 feet to ensure it complements the main residence and the neighborhood.
Building Coverage
The ADU must not exceed 50% of the total lot coverage allowed for the property.
Location
| Property Type | Location Requirement |
| Single-Family Homes | Attached ADUs: Must share a wall with the primary residence |
| Detached ADUs: Must be located in the rear or side yard | |
| Junior ADUs (JADUs): Must be within the existing primary residence | |
| Duplex and Multifamily | Attached ADUs: Must be integrated into the existing structure |
| Detached ADUs: Must be located in the rear or side yard |
Exterior details
ADUs in Sunnyvale must match the exterior materials, colors, and design of the primary residence to ensure architectural consistency.
Parking
At least one parking space per ADU is required, which can be provided as tandem parking on an existing driveway.
Setbacks and Buffer Zones
ADUs must adhere to a minimum setback of 4 feet from the side and rear property lines, ensuring proper spacing and privacy.
Minimum Lot Area
| Lot Size | Minimum Lot Area for ADU | Description |
| Under 7000 | ADUs not permitted | Lot size is too small for additional units |
| 7000 - 9999 | 7000 sq ft | Sufficient space for small ADUs |
| 10000 - 12999 | 10000 sq ft | Suitable for medium-sized ADUs |
| 13000 - 19999 | 13000 sq ft | Adequate for larger ADUs |
| 20000+ | No minimum lot area requirement | Flexible for multiple or larger ADUs |
Connection for utilities
All ADUs must have independent utility connections for water, sewer, and electricity to ensure functionality and compliance.
Fire safety
ADUs in Sunnyvale must meet all fire safety regulations, including the installation of smoke detectors and fire extinguishers.
Room specifications
- Sleeping Areas: Each sleeping area must have an egress window and sufficient natural light.
- Kitchen: Must include a sink, refrigerator, cooking appliance, and storage space.
- Bathroom: Should have a toilet, sink, and either a shower or bathtub.
- Storage: Adequate storage spaces must be provided within the ADU.
Short-term Rentals and Home Occupations Regulations
Short-term rentals of ADUs are permitted with proper registration and adherence to city ordinances.
Building Codes
ADUs must comply with all local building codes, including structural, electrical, plumbing, and mechanical standards.
Sunnyvale ADU Permit Guidelines
| Permit Type | Description | Estimated Fee |
| Building Permit | Required for ADU construction. | $2500 - $5000 |
| Electrical Permit | Needed for electrical work. | $400 - $700 |
| Plumbing Permit | Needed for plumbing installations. | $400 - $700 |
| Mechanical Permit | Needed for HVAC systems. | $400 - $700 |
| Grading Permit | Needed for site grading. | $300 - $500 |
| Site Development Permit | For developing the site. | $300 - $500 |
| Zoning Permit | Ensures compliance with zoning laws. | $200 - $400 |
Property Requirements
ADUs in Sunnyvale must be built on properties that meet zoning, size, and setback requirements to ensure compatibility with neighborhood standards.
Parking
One off-street parking space is required per ADU, which can be configured as tandem parking.
Front setbacks
ADUs must maintain a minimum front setback of 20 feet to preserve the streetscape.
Side and rear setbacks
Minimum setbacks of 4 feet from side and rear property lines are required to ensure privacy and space.
Open space and rear yards
ADUs must not encroach on required open space or rear yard areas, preserving outdoor living spaces.
Properties That Qualify
To determine your property’s eligibility for ADU development, contact the Sunnyvale Planning Department.
- Verify that your property is within Sunnyvale’s jurisdiction.
- Check the specific residential zones that permit ADUs. Common zones in Sunnyvale include R-1, R-2, and R-M.
- Other General Plan designations that permit ADUs:
- Residential Mixed-Use (RMU): This zone allows for flexible residential development, including ADUs.
- Transit-Oriented Development (TOD): ADUs are encouraged near transit hubs to promote sustainable living.
- Specific Plan areas: Designated areas with unique development guidelines that may permit ADUs.
Development standards
Single-family
- Attached: Must have a shared wall with the main residence and adhere to size limits.
- Detached: Can be placed in rear or side yards, with height and size restrictions.
Duplex properties
- Attached: Must be incorporated into the existing structure and meet specific design criteria.
- Detached: Permitted in rear or side yards, respecting setback and height limitations.
Multifamily properties
- Attached: Can be built within the existing building envelope, subject to floor area ratios.
- Detached: Allowed in designated areas, complying with spacing and design regulations.
Junior ADUs (JADUs)
JADUs must be within the primary residence, limited to 500 square feet, and include a kitchenette and separate entrance.
Property designations
- Flood Zones: ADUs in flood zones must comply with additional elevation and flood-proofing requirements.
- Geohazard Zones: Properties in geohazard zones require extra geological assessments before ADU approval.
- Historic Designation: ADUs on historically designated properties must maintain architectural integrity and receive approval from heritage committees.
- Easements: ADUs must not encroach on utility or access easements, ensuring clear pathways for maintenance and emergencies.
Summary
Sunnyvale provides a supportive environment for ADU development with clear regulations designed to balance growth with community standards. Navigating these rules can be complex, but ADU Specialist Bay Area offers expert guidance to help you every step of the way, from initial planning to final construction.
FAQ
ADUs in Sunnyvale must not exceed 16 feet in height, ensuring they are compatible with surrounding buildings and do not overshadow neighboring properties.
No, properties under 7000 square feet are not eligible for ADU development in Sunnyvale due to space limitations and zoning regulations.
ADUs must have a minimum setback of 4 feet from side and rear property lines, ensuring adequate spacing and privacy.
Yes, ADUs must match the exterior design, materials, and colors of the primary residence to maintain neighborhood aesthetics.
The maximum size for an ADU in Sunnyvale is 1,000 square feet, providing ample space for comfortable living.
Yes, ADUs must have independent utility connections for water, sewer, and electricity to ensure proper functionality and compliance.
The standard permitting process takes approximately 60 days, but this can vary depending on the complexity of the project.
Yes, two-story ADUs are allowed, but they must adhere to a maximum height of 16 feet and other design criteria.
Properties in residential zones such as R-1, R-2, and R-M are generally eligible, as well as those in designated mixed-use and transit-oriented areas.
Yes, one off-street parking space is required per ADU, which can be tandem parking on an existing driveway.
Yes, short-term rentals are allowed with proper registration and adherence to city ordinances.
ADUs must meet all local fire safety regulations, including smoke detectors and accessible fire extinguishers.
Yes, ADUs must adhere to all local building codes, including structural, electrical, plumbing, and mechanical standards.
Yes, but ADUs in historic districts must maintain architectural integrity and receive approval from heritage committees.
Contact the Sunnyvale Planning Department to verify property eligibility, including zoning and lot size requirements.
Yes, specific plan areas with unique development guidelines may permit ADUs, offering additional opportunities for development.
Duplex properties can have attached or detached ADUs, adhering to specific size, setback, and design requirements.
Yes, multifamily properties can have attached or detached ADUs, complying with floor area ratios and design regulations.
JADUs must be within the primary residence, limited to 500 square feet, and include a kitchenette and separate entrance.
Yes, properties in geohazard zones require geological assessments before ADU approval to ensure safety and compliance.
ADUs must not encroach on utility or access easements, ensuring clear pathways for maintenance and emergencies.
Properties must be at least 7000 square feet to qualify for ADU development, ensuring sufficient space for the unit and required setbacks.
Yes, but the ADU must meet specific size, setback, and design criteria to ensure compatibility with existing structures.
ADUs must match the primary residence’s exterior materials, colors, and design to maintain neighborhood aesthetics.
ADU Specialist Bay Area provides expert guidance, from initial planning through final construction, ensuring compliance with all local regulations and a smooth development process.
