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Prefab ADU in San Mateo

Abodu makes and installs prefab homes for play, passive income and possibility in as little as 6 months.

About San Mateo

Maximize the possibilities by custom-building an Abodu prefab ADU in the city of San Mateo. Between enhancing your property value and providing a dedicated space for work, relaxation, or family, accessory dwelling units offer an abundance of opportunities.

With Abodu, you can build an ADU based on your exact preferences, no matter if you’re dreaming of luxe appliances or distinctive finishes. From two-bedroom, two-bathroom modular homes to efficient studios, Abodu’s range of prefab ADUs merges exceptional style, functionality, and thoughtful design.

Crafted with precision in specialized production environments, an Abodu ADU boasts superior quality and a relatively fast turnaround—most are ready in nine months, so you can start enjoying your new living space in less than a year.

What are the benefits of having an ADU?

ADUs are a worthwhile investment for homeowners that combine functional versatility with notable financial benefits. In many cases, secondary units have the potential to generate rental income and boost the value of your real estate by around 30%.

And given the high demand for affordable housing in California, leasing a prefab ADU in San Mateo can provide you with consistent rental income every month. Keep in mind that the city’s median rent is roughly $3,300.

In terms of function, ADUs have a vast range of uses. For example, an in-law unit or granny flat can house family members as an independent living space, or you could convert the secondary unit into a home office, personal gym, or guest house.

The flexibility of an ADU to adapt to changing needs—whether for family, work, or leisure—makes it a practical addition to any primary residence in the San Francisco Bay Area, from San Jose to Redwood City.

An Abodu being installed in San Jose

An Abodu being installed in San Jose

San Mateo ADU requirements

Between acquiring proper building permits and securing funding, there are multiple considerations involved in the process of constructing a prefab ADU in San Jose.


How much does an ADU unit cost in San Mateo?

A prefab ADU in the city of San Mateo can cost upwards of $500,000 when you take into account expenses related to architectural consultations, construction, and labor.

Based on the San Mateo County ADU calculator, this estimate includes many factors, such as design—whether it’s a high-end build or standard model—site conditions, square footage, and number of bedrooms and bathrooms.

For reasonable and upfront pricing, choose proven prefab ADU builders like Abodu, offering secondary units that start at only $228,800. Plus, you can customize your ADU with premium features and finishes for a one-of-a-kind living space in your backyard.

Building Permits

How do I get an ADU permit?

The ADU permitting process in the city of San Mateo requires consulting the city’s planning division, then submitting a permit application package with your ADU project plans. After reviewing and approving the documents, the CDD will issue you an ADU building permit.

Another route to secure a permit is to partner with an ADU company. Using pre-approved designs, Abodu can often expedite the permitting process over other ADU builders.

As a result, homeowners can complete their ADU projects more quickly and easily, saving valuable time and resources in the process.


What facilities are required for an ADU?

San Mateo ADU ordinances require secondary units to have specific utilities to qualify as an independent living space, including connections to gas, water, sewer lines, and electricity.

Homeowners may also need to pay development impact fees, such as charges for wastewater capacity. For ADUs, the city of San Mateo applies these fees per square foot.


How do I fund an ADU unit in San Mateo?

There are many ADU financing options available, with home equity lines of credit (HELOCs), cash-out refinancing, and construction loans being the most popular.

With a HELOC, you can leverage the market value of your property to open a line of credit and draw funds to cover ADU construction costs. Then you’ll make payments in monthly installments.

Alternatively, cash-out refinancing allows you to restructure your primary mortgage for a higher amount, then you can use the difference to fund your ADU project.

Securing a construction loan is another path. Intended for new construction projects, this financial option is a short term loan that typically lasts for one year. It will either need to be paid in full once the project is complete or refinanced into a different type of loan, usually a mortgage.

FAQs: Prefab ADUs in San Mateo

For a new accessory dwelling unit in the city of San Mateo, residential property owners can expect to pay around $1,500 to $3,000 in fees for the building permit. It’s worth noting that a wide range of variables—from appeals to additional filings and inspections—throughout the permitting process could result in higher costs.

The first phase of a new ADU project in San Mateo is thorough research and site planning. Look into local zoning requirements (e.g., heritage trees, flood plain status, etc.) and building codes for ADUs.

Then determine the design and configuration of your prospective prefab ADU, keeping in mind factors like setbacks, lot size, and property lines. Include these essential details in your building permit application.

Note that whether you own a multi-family or single-family lot may affect how you can build your secondary unit. Next, schedule a consultation with the city’s Community Development Department (CDD)—this can take place over the phone, through email, or in person.

During the consultation, the staff member will confirm that your ADU project complies with the jurisdiction’s regulations for zoning and permitting. Afterward, you can submit your permit application for review.

Following city approval and permit issuance, your ADU builders can begin crafting your modular home. And since construction happens off-site, there's minimal disruption to your daily life, making it a smooth and hassle-free experience for both homeowners and neighbors.

Lastly, when production of your secondary unit is complete, you can arrange for its delivery and on-site installation.

Both city and state law do not specify a maximum size for most standard secondary units, though a junior ADU (JADU) can be up to 650 sq.ft. in San Mateo. For conventional ADUs larger than 800 sq.ft., factors like the zoning district’s floor area ratio may determine the unit's upper size limit.

What appliances are typically included in an ADU? 

As self-contained living spaces featuring a full kitchen, these modular homes usually come with the following appliances:

  • Refrigerator

  • Dishwasher

  • Oven

  • Stove or cooktop

  • Range hood

  • Garbage disposal

  • HVAC system

  • In-unit washer and dryer

The exact appliances you'll find in a detached ADU varies depending on each model’s specific design, size, and configuration.

How long does it take to build an ADU?

The timeline for building a prefab ADU in the city of San Mateo can span several months to over a year. This includes planning, obtaining permits, construction, and final inspections.

Prefer efficiency and speed? Then choose Abodu, where your new ADU can likely be completed with a quick turnaround time of just nine months.

Build your dream prefab ADU in San Mateo

Abodu has a track record of excellence and is committed to sustainable, high-quality prefab ADU design and construction. From navigating the complexities of permits to perfecting the precision of crane delivery, our team manages every aspect of the ADU building process. Imagine a timeless living space that not only complements, but elevates your lifestyle. No matter your vision, Abodu can make it a reality. Book a call or showroom tour today.

Learn more about Abodu Prefab ADUs

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All-in-One Service

Featuring an impressive selection of pre-approved plans, Abodu streamlines the process of building and installing premium built-to-order ADUs.

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Unparalleled Design

Each floor plan showcases timeless designs using sustainable, high-quality materials—all with upfront pricing.

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Committed to delivering a straightforward, hassle-free experience for California homeowners, our efficient approach to prefab ADUs lets you enjoy your newly added living space as soon as seven months after signing on the dotted line.

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A Great Investment

Take advantage of an exceptional return on investment with an Abodu ADU.

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Book a call or tour today.