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Top Rated Contractor for Custom ADU in Los Altos Hills, 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 - from project managers, architects, builders, to contractors -  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 Los Altos Hills, California

Building a custom-built ADU in Los Altos Hills, 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 Los Altos Hills?

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


What are the Standards and Rules for Building an ADU in Los Altos Hills?

Here’s a compilation of answers to frequently asked questions about the standards and rules for building a high quality ADU in Los Altos Hills.


What zones are allowed to build an ADU in Los Altos Hills?

R-A (Residential Agricultural) .


What is the minimum ADU size in Los Altos Hills?

150 square feet.


What is the maximum ADU Size in Los Altos Hills?

  • 1000 sq ft maximum if the ADU is built 4 feet from the side and rear property lines.

  • 1200 sq ft maximum if the ADU meets the standard 30-foot rear and side setbacks.

  • The maximum size of a detached accessory dwelling unit that is a studio or with one bedroom is eight hundred fifty (850) square feet.

  • The maximum size of an accessory dwelling unit with more than one bedroom is one thousand (1,000) square feet.

  • The maximum size of an attached accessory dwelling unit is one thousand (1,000) square feet or fifty (50) percent of the primary dwelling’s living area, whichever is less, provided that at least eight hundred (800) square feet is allowed.

  • The maximum size for a Junior ADU is 500 square feet, unless it includes one additional on-site parking space, in which case the maximum size may be increased to 650 square feet.


What is the maximum allowable height for ADU in Los Altos Hills?

  • Maximum ADU height is 16 feet if the ADU is built 4 feet from rear and side property lines.

  • Maximum height increases to 19 feet if the ADU is built 30 feet (standard setbacks) from the rear and side property lines.

  • A detached ADU in Los Altos Hills can have a second story as long as it meets standard height requirements.

  • An attached ADU in Los Altos Hills can reach a maximum of the same height as a primary dwelling (27 feet) if it meets the standard setbacks (30 feet).


What are the required setbacks for ADUs in Los Altos Hills?

  • For ADUs up to 1000 sq ft, setbacks must be 4 feet from the side and rear property lines.

  • For ADUs up to 1200 sq ft, both rear and side setbacks must be 30-foot.

  • There are no special setbacks for corner lots.

  • There is no minimum or maximum distance required between the primary residence and ADU.

Are there any lot or location restrictions for ADUs in Los Altos Hills?

Yes. The maximum floor area and development area (paved area) of the parcel are calculated by formula. Up to 800 sq ft floor area and development area are exempted for an ADU.

What are the parking requirements for JADUs or ADUs in Los Altos Hills?

JADUs do not require any additional parking, while ADUs typically require one parking spot unless specific criteria are met. These exceptions include being within one-half mile walking distance of public transit, within one block of a car share vehicle, on a street where on-street parking permits are required but not offered to the occupant of the ADU, or if the ADU is built as part of a new home. 

What must comply with other design guidelines for ADUs in Los Altos Hills?

  • Designs of detached ADU in Los Altos Hills must relate to the design of the primary dwelling by using similar exterior wall materials, identified color tones, window types, door and window trims, roofing materials and roof pitch.

  • For attached units in Los Altos Hills, the ADU must be constructed so that the entire structure appears to be one dwelling including building form, colors, window styles, and window and door trims.

  • Detached ADUs in Los Altos Hills that are within thirty (30) feet of a side or rear property line, the exterior entrance shall not face a side or rear property line.

  • Exterior wall colors and materials shall have a light reflectivity value (LRV) of fifty (50) or less and roof materials shall have a light reflectivity value (LRV) of forty (40) or less.

  • Exterior building light fixtures shall be shielded and downward facing, and limited to one exterior light fixture per exterior doorway, or the minimum necessary to comply with the California Building Standards Code.

What are the other requirements for ADUs in Los Altos Hills?

  • Areas encumbered by a recorded easement (including, but not limited to, access easements, conservation easements, general public easements, open space easements, pedestrian pathway easements and public utility easements;

  • Areas with slopes that meet or exceed thirty (30) percent;

  • Areas within twenty-five (25) feet of the top of a creek bank;

  • Areas within a geotechnical or seismic hazard zone. Review and approval of a geotechnical and/or geologic report prepared by a licensed geotechnical engineer or registered civil engineer is required in order to locate a structure within a geotechnical or seismic hazard zone;

  • Areas within the critical root zone of a heritage oak pursuant to Section 12-2.300. Review and approval of an arborist report prepared by a licensed or consulting arborist is required if a structure is proposed within the critical root zone of a heritage oak tree.

  • Note: Town engineer will review grading and drainage plans per engineering standards. There are no special requirements for ADU grading and drainage plans.

Is there any Owner-Occupancy Rule for JADU in Los Altos Hills?

Yes. Owner must occupy either the JADU or the primary house.

Are there any deed restrictions when building accessory dwelling units in Los Altos Hills?


What is the renting regulation for JADUs or ADUs in Los Altos Hills?

An ADU or JADU must be rented for a period of no less than thirty-one (31) days, and cannot be occupied as a short-term rental unit.

What are the Departments/Agencies involved in the permit application process for ADU in Los Altos Hills?

Planning, Building, Engineering, the County Fire Department, the County Department of Environmental Health (if the property is not connected to sewer), and Geotechnical Review (if the property is in a geo hazard zone).

What are the specific rules for JADU in Los Altos Hills?

If a JADU provides one additional on-site parking space, the maximum size may be increased to six hundred fifty (650) square feet.

What are the fees for ADUs in Los Altos Hills?

  • Planning Pre-Application Review Meeting = $410

  • Building Permit Fee = $240+0.9% of project evaluation

  • ADUs are not subject to City impact fees. ADUs may still be subject to impact fees assessed by non-City public agencies, such as School District fees or Fire District fees.

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 Los Altos Hills?

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 Los Altos Hills?

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 Los Altos Hills?

You can do a Google Search for the keyword “adu contractor near me” or get referrals from your friends or local community in Los Altos Hills CA. 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 Los Altos Hills?

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 Los Altos Hills?

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 projects in Los Altos Hills, 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,

  • separate 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 Los Altos Hills

Nestled among the rolling hills of the San Francisco Bay Area, Los Altos Hills, California, is a quintessential slice of Silicon Valley life. With a land area of over eight square miles and a population that cherishes its rural charm within a technologically advanced hub, Los Altos Hills stands as a beacon of community living. For those seeking to escape the urban bustle without compromising on contemporary conveniences, the town offers a tranquil oasis with close proximity to thriving city centers.

Historical Insights

Founded in 1924 by the "Father of Los Altos Hills," George E. Diss, the town has seen its share of historical moments. Diss cultivated a vision of maintaining a rural and residential community, a blueprint that remains intact to this day. The town's early years were marked by influential leaders forging a unique identity, as it emerged from the shadows of its larger, neighboring cities.

Significant milestones include Los Altos Hills serving as the backdrop for the organizational meetings of the Homebrew Computer Club, which ultimately catalyzed the personal computer revolution. The club counted among its members a young Steve Wozniak, who would later co-found Apple Inc.

Unique Geography

Los Altos Hills' most obvious feature is its undulating topography. The hills provide stunning panoramic views of the San Francisco Bay, the Pacific Ocean, and the idyllic Stanford University lands. Residents here enjoy nature's private amphitheater with its sunsets and silhouettes of surrounding mountain ranges. The town is also home to Byrne Preserve, a cherished open space offering hiking trails and a respite from the digital clamor of the Valley.

The geography of the area is not just scenic but also accessible. The miles of trails offer any hiker, biker, or horseback rider the freedom to roam without venturing too far from the pastoral life.

Notable Residents

Los Altos Hills has become something of a who's who among the tech and business elite. It's not uncommon to spot a celebrity or industry influencer browsing the aisles of the local farmers' market. Among its prestigious residents are pioneers and innovators like Google co-founder Sergey Brin, former Yahoo CEO Marissa Mayer, and Oracle's Larry Ellison. These individuals are part of a community that takes pride in its collective accomplishments and commitment to excellence.

Local Culture and Events

The town's genteel culture and spirit of volunteerism are evidence of a community that deeply values camaraderie and civic service. Local events such as 'Film Nights in the Hills' and the 'Fiesta Days Parade' serve as touchstones for these shared values, with the entire community coming together to celebrate. There's also a strong emphasis on giving back, with residents actively involved in philanthropy and supporting worthy causes, an ethos that is reflected in the town's many charitable events and outreach programs.

Real Estate Highlights

The real estate in Los Altos Hills mirrors the sophistication and meticulous detail that characterize the area. Architectural wonders like modernist masterpieces and high-tech smart homes dot the landscape, interwoven with sprawling ranch estates. Despite being dubbed the "Beverly Hills of the Bay Area," Los Altos Hills maintains a humble approach to its property values and market trends, which continue to climb.

On any given day, the local real estate market is abuzz with buyers seeking their own piece of paradise. The allure of owning property in this exclusive enclave extends beyond the tangible, resonating with the promise of a lifestyle that harmonizes luxury with a love for nature and community.

There were 71 ADUs that received building permits in Los Altos Hills in 2018 and 2019. 97 % of these were intended to be made available to renter.


There are about  8,423 people living in Los Altos Hills. Average income is around $236,304 and average property is value is at $1,999,967.

Los Altos Hills is more than just a wealthy suburb; it's a town with a poignant history, a vibrant present, and a promising future. For those looking to experience life at the intersection of technology and tranquility, Los Altos Hills is a tapestry of breathtaking landscapes, rich culture, and awe-inspiring achievements. The town beckons individuals to not just live within its hills but to become a part of its wondrous, enduring narrative. Whether you're a history buff, a nature enthusiast, or a home seeker, Los Altos Hills is bound to captivate you with its charm and allure. It's time for you to explore and appreciate all that this hidden gem has to offer.

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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