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Top Rated Contractor for Custom ADU in Cupertino, California

Featured Project

Located in Pleasanton, this detached accessory dwelling unit measures up to 440 square feet. It has a kitchen, bathroom, bedroom, living room, walk-in closet, and a utility room. 

With proper design, it’s amazing how we’re able fit all these amenities in this secondary dwelling unit. We have to say that it’s even more fulfilling to have a custom-built ADU with personalized designs and layouts that fit your lifestyle needs. One interesting thing about this ADU is the addition of a patio just outside the ADU since Christina loves to cook and gather with friends.

Watch this video to take a look inside this beautiful custom-built ADU:


Cristina has been living with her mother for a year and a half. After some time, she realized she wanted to have her own space so they talked about building an Accessory Dwelling Unit (ADU).

The thought of building a custom-built ADU in Pleasanton was a win-win solution because she can finally have a space of her own and, in the future, she could rent it out to tenants, giving her additional source of passive income.


What this video as Christina shares with you her experience in building her own detached ADU from start to finish.

About ADU Builders Group

At ADU Builders Group, we are on a mission to revolutionize how homeowners in the Bay Area expand their living spaces. Our core dedication lies in helping these homeowners effortlessly build their Accessory Dwelling Units (ADUs) by streamlining every step of the process. With the rising need for additional living space, our company offers a timely solution that not only increases property value but also supports multi-generational living and generates potential rental income.


Our Expertise

We specialize in creating customized livable spaces tailored to fit the needs of every homeowner. Our product range includes:

Accessory Dwelling Units (ADUs)

Independent living units equipped with their own sleeping, cooking, and bathroom facilities.

Attached ADUs

These units share a wall with the main home, perfect for those looking to maintain close proximity to their additional living space.

Detached ADUs

Stand-alone units that offer privacy from the main home, ideal for renters or as guesthouses.

Junior ADUs (JADUs)

Smaller living units converted from existing spaces within the main home, such as bedrooms or garages, offering a compact but fully functional living solution.


Why Choose Us?

Our commitment to excellence and customer satisfaction is reflected in our unique selling points:


3 Years Service Warranty with Complimentary Annual Inspection

We stand behind the quality of our work with a 3-year service warranty on all our custom-built ADUs, ensuring peace of mind for our clients. To further assure the durability and maintenance of your investment, we provide a complimentary annual inspection, making sure your ADU remains in peak condition. This service warranty is on-top of 10-year standard warranty on structural components.


Streamlined Process

Understanding the complexity involved in building a custom-built ADU, we've refined our processes to offer an effortless experience. From initial design consultation to final walkthrough, our team of experts is with you at every step, ensuring a seamless transition from vision to reality.


Customizable Solutions

Recognizing that every homeowner's needs are unique, we offer fully customizable ADU solutions. Whether you're looking for a cozy JADU for family or a spacious detached ADU for rental income, we adapt our designs to meet your specific requirements.

Our Commitment


At ADU Builders Group, we’re more than just home builders building custom ADUs. We’re about creating valuable, functional spaces that enhance lifestyles and bring visions to life. With a keen focus on innovation, quality, and customer satisfaction, we are dedicated to transforming the way the Bay Area thinks about home expansion.


Contact us today by filling out the form below to take the first step towards building your own custom-built ADU.

How to Build an ADU in Cupertino, California

Building a custom-built ADU in Cupertino, California can be summarized into a seven-step process:

  1. Get Started

  2. Learn The Rules

  3. Set your Budget

  4. Design your ADU

  5. Apply for Permits

  6. Build your ADU

  7. Rent it Out or Move It

How to get started with ADU?

You can start with your ADU by thinking about what you want and asking yourself these questions:

  • Who am I building this for?

  • What are the amenities I need to add into this project to support my family members, my tenant, or my own needs?

  • How can it improve and support my lifestyle?

If you’re looking for an inspiration, you can go check your local neighborhood for anyone who owns a casita, visit online community groups for ADU on Facebook and other social media channels, check these floorplans compiled by Santa Clara County ADU, search for “ADU contractor near me” and check portfolios of local ADU builders in your area, or simply consult with us at ADU Builders Group by filling out the form below.


What are the Standards and Rules for Building an ADU in Cupertino?

Here’s a compilation of answers to frequently asked questions about the standards and rules for building an ADU in Cupertino.


What zones are allowed to build an ADU in Cupertino?

All zones that allow residential development. 

What is the minimum ADU size in Cupertino?

150 square feet.

What is the maximum ADU Size in Cupertino?

  • For Junior ADUs (JADU) or internal conversions, there is no maximum size limitation.

  • For a single family home residence, a detached ADU in Cupertino can be up to 800 square feet. For ADUs exceeding 800 square feet, whether attached or detached, these ADUs will be limited by lot coverage, floor area ratio, and open space requirements.

  • For multi-family developments, A detached, non-streamlined ADU can be up to 1,200 square feet. 


How many  ADUs can I build, at most, on my property in Cupertino?

Pursuant to AB 3182, adopted in 2020, single family properties can construct a JADU and a streamlined detached ADU (≤ 800 sq. ft.) or an ADU that is a conversion of existing space built in accordance to the City of Cupertino's Municipal Code, for a total of two ADUs. 


Note that a JADU cannot be combined with either an attached ADU,or a detached ADU that is greater than 800 sq. ft. For multi-family property, you can construct up to two detached ADUs and convert non-habitable spaces to construct up to 25% of the number of existing units (minimum one unit) as ADUs.


How many bedrooms can I have in my ADU in Cupertino?

You can have up to 2 bedrooms.

What is the maximum allowable height for an ADU in Cupertino?

ADUs may be up to 18 feet. However, detached ADUs in Cupertino usually can have up to 16 feet. Moreover, Detached two story ADUs are typically not permitted. A two-story ADU is only allowed if you are converting a portion of existing second story space into an ADU.

What are the required setbacks for ADUs in Cupertino?

Required setback is 4 feet unless replacing an existing structure. Additionally, Detached ADUs must have a 5-foot separation between the eaves of the structure and the primary house.

Are there any lot or location restrictions for ADUs in Cupertino?

Yes. Non-streamlined units must meet zoning standards.


What are the parking requirements for a streamlined ADU in Cupertino?

None, there is no parking required for streamlined ADUs in Cupertino.


What are the parking requirements when building a non-streamlined ADU in Cupertino?

One additional space is required unless the ADU is:

  • Located within one-half (1/2) mile of a public transit stop.

  • Located in an architecturally and historically significant historic district.

  • The occupant of the unit is not allowed/offered a required on-street parking permit.

  • Located within one block of a car share vehicle pick-up location.

  • Is part of the proposed or existing primary residence or an accessory structure.


What are other requirements when building an ADU in Cupertino?

Another requirement is a Boundary or Lot Survey.

Is there any Owner-Occupancy Rule for ADU in Cupertino?

Yes. On a property with a Junior ADU, the property owner must live in either the Junior ADU or the primary dwelling unit. Additionally, ADUs, including JADUs, may not be used for short-term rental activity. 


Are there any deed restrictions when building accessory dwelling units in Cupertino?

Yes. Recording of deed restriction documenting JADU-related owner-occupancy rules.


What is the regulation for renting accessory dwelling units or ADU in Cupertino?

Generally, ADUs and JADUs cannot be rented for fewer than 30 days at a time.


What are the Departments/Agencies involved in the permit application process for ADU in Cupertino?

  • City of Cupertino - Planning, Building, Public Works, Environmental Services.

  • Outside Agencies - Santa Clara County Fire, Cupertino Sanitary or, Sunnyvale Sanitary, San Jose Water.


What are the fees for building an ADU in Cupertino?

City impact fees are waived for ADUs below 750 sq ft. Sample fee for a new 743 sq. ft. Detached ADU is listed below:

  • Advanced Planning Fee - $163.46

  • Construction Tax - $901.29

  • Strong Motion Fee Cat. 1 - $35.1

  • CBSC Fee - $11

  • Plan Check - $1780

  • Inspection - $2223

  • Address Assignment - $446

  • Total: $5,559.85

You may refer to Local Rules & Contacts - Santa Clara ADU , then select your city to check for the latest rules in your area. Check with your local city as well to assess your property and ascertain its suitability for an ADU. Determine the type of ADU you can build based on your local zoning laws and the physical characteristics of your property.

How much does it cost to build an ADU in Cupertino?

For custom ADUs, the estimated cost per square foot can range from $450 - $500. You can start planning your budget using this estimate. You may also contact us for a more detailed quotation by filling out the form below. 


You may also be interested to look into financing options.

How to finance an ADU in Cupertino?

To finance your ADU, you have several options from loans, HELOC, to grants.



Several loan options exist for financing an ADU project. A home equity loan, for instance, allows you to borrow against the equity you've built up in your home. Another alternative is a construction loan, which is a short-term loan that covers the cost of construction. Once the construction is complete, the loan can either be paid off or converted into a standard mortgage.


Home Equity Line of Credit (HELOC)

Similar to a home equity loan, a HELOC also lets you borrow against your home's equity. However, it works more like a credit card, where you have a line of credit you can draw against as needed.



In certain situations, grants may be available for ADU construction. Some local and state programs offer grants, especially targeted at homeowners looking to build ADUs for low-income renters or seniors. It's worth researching local initiatives and programs in your area. The CalHFA 40k ADU Grant is one notable grant to look into.


Do you have financing options?

Yes, we partner with reputable finance companies to help our clients build their ADU as soon as possible.

How to Design your ADU?

You can start by getting some inspiration then hiring a professional architect to lay out your vision for you. It would even be better to look for a reputable local ADU contractor in your area that offers both design and build services.


Discuss your initial design with the local Planning staff. After revisions, finalize your design and have your contractor prepare the plans for permitting.


How to find the right local adu contractor near me in Cupertino?

You can do a Google Search for the keyword “adu contractor near me” or get referrals from your friends or local community. Then go on checking their credentials, licenses, and insurance. Review their portfolios and ask for references. Get multiple quotes and compare. Prioritize clear communication and trust your instincts.


Do You Need a Permit for an ADU in Cupertino?

Yes. Start by confirming application requirements with your local staff. Then, submit your application online or in-person and pay any required fees. Staff will review your application within 60 days, and often sooner. Revise your application if needed. Staff will tell you the best way to be in contact, likely via email. Generally, outstanding fees are due before your permit is issued.  


How to Build your ADU in Cupertino?

The best way to do it is by working with a reputable contractor like ADU Builders Group. We’ll handle everything you need for your ADU from design to moving in. We believe that in every successful project, the key is effective communication. That’s why, we’ll regularly update you with the progress of your project for your peace of mind.


Rent it Out or Move In 

After passing the final inspection, it’s ready for move-in! A bit of landscaping would be advisable if you prefer to beautify and add more personality to your property. Enjoy your new ADU! 



Check out this overview of the entire ADU process prepared by the Santa Clara County ADU.

What is an Accessory Dwelling Unit?

ADUs are self-contained secondary living units that share the same lot as a primary residence. They can be either attached or detached from the primary residence and are often smaller in size. An ADU typically has its own entrance, kitchen, bathroom, and living space. It can come in different forms such as a basement apartment, converted garage or attic space, or a separate building on the property.

ADU is also sometimes referred to as one of the following depending on their uses or for whom it is built:

  • granny flats,

  • in-law suites,

  • backyard cottages,

  • secondary suite,

  • secondary dwelling unit, or

  • casita.

Whatever people choose to call it, the primary purpose of ADUs,both prefab and custom-built, is to provide additional housing options for homeowners. They can be used for various purposes such a

  • accommodating aging parents,

  • independent living space for adult children, or

  • source of rental income.




Rising Demand of ADUs in California

California, known for innovation and opportunity, attracts dreamers and visionaries from all over the world. However, behind its successful appearance, there is a growing housing crisis that has been getting worse for years.


Despite its technological advancements, cultural diversity, and economic prowess, the state faces shortage of affordable housing. Factors contributing to this housing shortage are population growth, limited construction, strict zoning rules, and high real estate prices. This makes it difficult for average earners to find affordable homes. In the face of this crisis, ADUs have emerged as a promising solution.


From 3,163 ADUs built in 2018, this number has risen to 13,439 in 2022, indicating a 325% increase in the number of ADUs built. These data are based on a report from UC Berkeley’s Center for Community Innovation. Since then, the concept of accessory dwelling units (ADUs) has been continuously gaining popularity in the housing market.



What are the Benefits of having an ADU on your Property?

Having an ADU on your property can offer several benefits to you such as providing an opportunity to earn extra income by offering it as a rental property or allowing you to keep your families closer together while still having a sense of privacy and independence. Custom-built ADU offers a convenient housing option for aging parents, adult children, or guests.


Moreover, adding an ADU can potentially increase the overall value of your property.


ADUs can help address housing shortages as well by providing more affordable housing options in high-demand urban areas. They offer a smaller, more affordable alternative to traditional single-family homes. For individuals or families who cannot afford a traditional single-family home, ADUs are considered as a more affordable housing option.


ADUs can serve various purposes, including a rental unit, home office, guesthouse, or even a space for aging in place. The flexibility allows homeowners to adapt the space to their changing needs over time. That’s how you can benefit from building an ADU on your property.


What are Different Types of ADU?

When it comes to accessory dwelling units (ADUs), there are several different types that cater to diverse needs and property structures. Let's discuss the four types of ADUs mentioned in the ADU Handbook published by the California Department of Housing & Community Development.


Attached ADUs

Attached ADUs are an extension or addition to the primary residence. They are physically attached to the main building and might involve converting a garage or adding a new structure onto the existing house. This type of ADU is beneficial for those homeowners who want to maintain a direct connection between the main house and the ADU.


​Detached ADUs

Detached ADUs, on the other hand, are separate structures that are independent of the primary residence. These are often constructed in the backyard and can offer a greater degree of privacy compared to attached ADUs. Detached ADUs are a great option if your lot has ample outdoor space.


Converted Existing Space ADUs

Converted Existing Space ADUs involve transforming an already existing part of the home into a self-contained living space. This could mean converting a basement, attic, or even a section of the house into an ADU. This type of ADU is a cost-effective choice as it utilizes existing structures.


Junior ADUs

Junior ADUs (JADUs) are smaller in size, typically up to 500 square feet, and are located within the walls of the primary dwelling. They include their own separate entrance, as well as an efficiency kitchen. JADUs offer a more compact, yet self-sufficient, living arrangement.


Each type of ADU has its unique set of advantages and considerations. It's essential to assess your specific needs, local regulations, and the available space on your property before deciding on the most suitable type of ADU. Whether it be an attached ADU for easy accessibility, a detached ADU for added privacy, a converted existing space ADU for an economical solution, or a junior ADU for a smaller-scale dwelling option, you can find a variation that fits your needs.

Fun Facts About Cupertino

The bustling heart of Silicon Valley, Cupertino, isn't just the address of tech giants like Apple Inc.—it's a diverse and dynamic city teeming with history, innovation, and community spirit.  With a population as diverse as its landscape, this picturesque city is a hotspot for culture enthusiasts and tech-savvy locals alike. Journey with us as we uncover the essence of this cherished community, and you just might discover something new about the place you call home.

Historical Insights

What's in a name? In the case of Cupertino, it's a nod to history. Named after Arroyo San José de Cupertino, the meandering creek served as a lifeline for orchards and farms that once dotted the region. Steeped in the Gold Rush era, Cupertino's roots are firmly planted in agrarian traditions, a spirit that still resonates today, mingled with the dynamism of the Digital Age.

Tech Hub Connections

How did a site of pastoral peace transform into a global tech magnet? Proximity to the epicenter of innovation—Silicon Valley. Stemming from the garage operations of yore to the modern-day tech campuses, the city's growth mirrors that of the electronic revolution. Now, Cupertino boasts not only a legacy but a living embodiment of technology's power to shape cities and lives.

Cultural Highlights

Cupertino's identity isn't confined to the tech tag. The city's lifeblood is its vibrant social fabric, interwoven with a diversity of traditions and celebrations. From the annual Cherry Blossom Festival to local arts showcases, it's evident that Cupertino cherishes its cultural tapestry, constantly adding vibrant threads that reflect its populace.

Nature's Bounty

The city is not just concrete and silicon; it's a haven for nature lovers. Cupertino revels in its stunning vistas and outdoor opportunities. Explore the lush pathways of Rancho San Antonio Preserve, or savor a serene moment among the blossoms at McClellan Ranch Park. These natural oases serve as rejuvenating sanctuaries amidst the buzz of city life.


Economic Landscape

Silicon Valley's ripples extend deep into Cupertino's economic growth. Diverse job opportunities and a thriving business scene underscore the city's position as a crucial economic player. Beyond tech, Cupertino prides itself on a spectrum of industries, contributing to a robust and resilient local economy.


Real Estate Tidbits

With a market as dynamic as its occupants, Cupertino's real estate scene is a reflection of its desirability. Boasting a range of neighborhoods, each bearing its distinctive character and charm, the city offers prospective homebuyers a mosaic of living options that cater to varied tastes and lifestyles.

There were 30 ADUs that received building permits in Cupertino in 2018 and 2019. None of those were intended to be made available to renter. There are about 59,276 people living in Cupertino. Average income is around $188,825 while average property value is at $1,776,601.

Home to Silicon Valley's prodigious tech companies, Cupertino is more than just their headquarters. It's a city brimming with liveliness and life, where history merges into the present, and the future looks as promising as the vistas against which it is being built. We invite you to explore and appreciate the remarkable facets of this gem within the valley, and perhaps uncover even more fun facts about Cupertino along the way, creating everlasting memories in a city that possesses a rich spirit of community and innovation.

Consult with Us.

Got inquiries? Wanna start building your own ADU?

Reach us out by submitting the form below.

Service Areas

  • ADU Palo Alto

  • ADU San Jose

  • ADU Santa Clara

  • ADU Saratoga

  • ADU Sunnyvale

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