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(408) 752-5614 ext: 374
Schedule ADU Consultation (408) 752-5614 ext: 374

Sunnyvale ADUs

Everything about building Accessory Dwelling Units in Sunnyvale, CA

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The city government of Sunnyvale has updated its local zoning codes to comply with the State ADU mandate.
The California Building Code (CBC) 2019 is adopted.

Last Updated 10/13/20


City Hint: The city permitted a total of 17 ADU projects in the past year of 2019, which is below the average compared to other cities in California.

Number of ADUs allowed:

According to state law, all single-family homes are allowed at least one ADU. Additionally, single-family lots which are owner-occupied may create one ADU and one Junior Accessory Dwelling Unit.

Multi-family. On lots that contain an existing multifamily dwelling structure,
(A) Two detached accessory dwelling units that meet the requirements in subsection ( d) of this section are allowed per lot.
(B) One or more accessory dwelling units may be created by converting interior non-liveable space under subsection ( e) of this section. The maximum number of accessory dwelling units so created shall not exceed 25% of the total number of dwelling units in the existing multifamily structure.

Types of ADUs allowed:

Detached ADU, Attached ADU, Junior ADU are permitted. ADUs may be new construction or converted from existing space. JADUs must be converted from existing space.

Lot size:

Residential properties will not be subject to any minimum lot size for Accessory Dwelling Units by ordinance or of the underlying zoning district. ~ According To AB68

ADU size:

Units up to 800 sq. ft. qualify for streamlined approval. For non-streamlined units - Maximum size. No more than 850 square feet gross floor area, or 1,000 square feet gross floor area if the unit has two bedrooms. However, if the accessory dwelling unit is attached to an existing single-family dwelling, the floor area of the accessory dwelling unit shall not exceed 50% of the existing single family dwelling.


Minimum four-foot side and rear-yard setbacks are required; however, setbacks of less than four feet are allowed if the accessory dwelling unit is constructed in the same location and to the same dimensions as an existing structure that is demolished for the purpose of constructing the accessory dwelling unit.


No new parking is required for a new ADU. Replacement parking not required when existing garage is converted. When ADU parking is provided, it must meet standards for development.

Fire Safety:

Accessory dwelling units shall not be required to provide fire sprinklers unless required for the primary dwelling.

Shape, materials and style:

Should maintain similar materials, colors, and appearance as the primary dwelling unit.


Height. The height of the unit as measured from within five feet of the structure is not more than 16 feet from the ground to the highest point on the roof

Design review:

Ministerial review process per state requirements. Design review shall not be required for minimal exterior changes that do not expand the existing structure.

Number of Bedrooms:

Not specified by State Standards.


Owner-occupancy will not be required for new ADUs (conversion and new construction) built between 2020 and 2025. ~ SB13 Update

Utility connections:

Utilities. The applicant may be required to install a new or separate utility connection directly between the accessory dwelling unit and the utility and may be subject to a connection fee or a capacity charge established by the city council that shall be proportionate to the burden of the proposed accessory dwelling unit, based upon either its size or the number of its plumbing fixtures, upon the water or sewer system. This fee or charge shall not exceed the reasonable cost of providing this service.


Off-street parking spaces for the accessory dwelling unit are not required if any of the following circumstances apply.
(i) The accessory dwelling unit is located within one-half mile of public transit.
(ii) The accessory dwelling unit is located within an architecturally and historically significant historic district.
(iii) The accessory dwelling unit is part of the existing primary residence or an existing accessory structure.
(iv) When there is a designated, fixed pick-up or drop-off location for a car share vehicle located within one block of the accessory dwelling unit.


Entrances and outside stairways serving accessory dwelling units shall not be constructed on any building elevation facing a public street.

Allowed Zones:

*** Beginning in 2020, according to state law, all residential zoning districts, including single-family and multi-family, are allowed to build Accessory Dwelling Units. ***

R-0, R-1, R-2, and Residential DSP blocks.

Lot Coverage:

At least one thousand square feet of open space is required for each R-2 lot with an accessory unit.


Conversions of Existing Interior Space. An application for a building permit to create one accessory dwelling unit per single-family lot in the R-0 or R-1 zoning districts shall be ministerially approved subject to the following requirements:
(1) The unit is contained within the existing space of a legally permitted accessory structure or single-family residence.
(2) The total size of the accessory dwelling unit is no less than one hundred fifty square feet.
(3) The unit has independent exterior access from the existing residence.
(4) The side and rear setbacks are sufficient for fire safety.
(5) The applicant shall not be required to provide an off-street parking space for the accessory dwelling unit. However, the applicant shall be required to replace any parking spaces lost as a result of the conversion of the existing space to an accessory dwelling unit.
(6) Design review shall not be required for minimal exterior changes that do not expand the existing structure.
(7) The applicant shall not be required to install a new or separate utility connection directly between the accessory dwelling unit and the utility, and shall not be charged a connection fee or capacity charge related to such requirement. The applicant may voluntarily install a new or separate utility connection, which shall be subject to the same fees.


No detached unit may be placed in front of the main dwelling.

Residential Building Code:

The California Building Code (CBC) 2019 is adopted.

Sunnyvale City Planning Offices

Sunnyvale Planning & Zoning

456 W. Olive Ave. Sunnyvale, CA 94086 Sunnyvale, CA 94086

Read Sunnyvale Housing Market Update

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ADU Design Library

Browse hundreds of models to find the right fit for your property.

ADU Model 536 sqft

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ADU Model 468 sqft

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ADU Model 540 sqft

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Customer Reviews

"Housable has been a great resource regarding my ADU project. I purchased both the Property and Design Reports. In both cases, they delivered as promised and on time."

Ed in Corona, CA

"My experience with Housable was exceptional. The team was extremely helpful and responsive. I am very satisfied and happy to have used these services. As a home owner I do not know the construction lingo or process but the Housable team very kind and helpful and patient with me. My expectations were exceeded. Thank you for everything."

Monica H. in Oakland, CA

"The property report was great! Made me feel like my project is feasible."

Alexandria in Santa Ana, CA

Complete 5-Step Process

Browse hundreds of permit-ready ADU designs and order one to customize to your needs.
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Select your contractor and build your project.

What our customers say:

Customer Reviews

"My permits were APPROVED, thank you for all your hard work. I am in the process of meeting with contractors. "

Mary S. in San Jose, CA

"I just wanted to let you know that the permit process has been completed and we are currently in the construction phase. The work you guys did was great and I will definitely be using this service again in the future. I will keep you guys updated on anything important. Thanks!"

Patrick L. in Orange County, CA

Detached ADU - Completed in 2020
1,003 sq. ft., 3 bed, 2 bath

Estimate Your ADU Potential
Costs / ROI



* upon completion of ADU


* based on local average price per sqft


* estimated by location


* 30 years / 5% interest rate / 20% down payment


Size: 500 sqft


Appreciation Estimate = (Base Value: $) / (Home's Living Space: sqft) * (ADU's Living Space: sqft)

Rental Estimate = (Rent Per Sqft: $4.51) * (ADU's Living Space: sqft)

Check your property's zoning, browse designs & get contractor estimates for your ADU project:

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