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Prefab ADU in Mill Valley

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

About Mill Valley

An Abodu prefab ADU in Mill Valley opens up a world of possibilities, whether you're looking to explore the potential of a rental unit, create a dedicated workspace, or in-law suite. With Abodu, you have the freedom to design your ideal living space, from the floor plan to the finishes, tailoring each detail precisely to your needs.

Take advantage of a more efficient and hassle-free building process with a prefab accessory dwelling unit crafted off-site. This type of ADU project significantly reduces on-site disruption, minimizing inconvenience to homeowners and neighbors during construction for a seamless experience.

What are the benefits of having an ADU?

Accessory dwelling units offer extra living space without the high costs or lengthy construction times of building a new home. In fact, Abodu can build your tailor-made prefab ADU in as little as six months. Not to mention, one of the top incentives for adding a secondary unit is its potential to boost property value by roughly 30%.

Constructed off-site, then delivered ready to use, prefab ADUs can provide a stable source of rental income. In an area with a shortage of affordable housing like Mill Valley and the greater San Francisco Bay Area, you could earn around $3,000 per month renting out a one-bedroom prefab ADU.

Plus, these modular homes boast incredible versatility. Use it as a home office, guest house, or housing for family members. A secondary unit gives aging parents or other relatives their own separate space while keeping them close by. No matter if you want to maximize your property's potential, help solve the housing crisis, or simply enjoy more flexibility, ADUs are a practical choice for many homeowners.

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Mill Valley ADU requirements

Marin County and Mill Valley ADU permitting procedures and construction standards help maintain public safety and neighborhood property values.


How much does an ADU unit cost in Mill Valley?

The cost of a prefab ADU in Mill Valley can range from $75,000 to $200,000, depending on the size, features, and customization options you choose. High-end finishes like hardwood floors and granite countertops can increase the final price tag substantially.

Building Permits

How do I get an ADU permit in Mill Valley?

To get an ADU construction permit in Mill Valley, builders have to provide thorough design specifications, including floor plans and structural plans, and supporting documentation. If the project plans meet local building codes and ADU laws, the city’s planning department will issue the proper permits.


What are the top ADU requirements in Mill Valley?

Mill Valley municipal regulations outline building codes for plumbing, electricity, sanitation, and parking requirements. These set the standards that every ADU project must follow, ensuring safety and compliance with local ordinances.


How do I finance an ADU in Mill Valley?

Property owners may fund their prefab ADU in Mill Valley with a home equity line of credit (HELOC), which provides access funds on an as-needed basis. Other financing options to consider include a construction loan, cash-out refinancing, and a traditional loan from a bank or another financial institution.

FAQs: Prefab ADUs in Mill Valley

According to the planning division fee schedule for the city of Mill Valley, an ADU building permit costs roughly $7,000 or more. This includes the planning fee for the pre-application review and design review in addition to the Southern Marin Fire District fee.

Multiple factors affect the ADU permitting process timeline, from the specific jurisdiction's processing times to the ADU project’s scope. Generally, securing a building permit in California can take anywhere from a few weeks to several months.

However, some cities and community development divisions work closely with trusted ADU builders, such as Abodu, granting pre-approval for certain prefab ADU designs. This expedites the approvals process, allowing these providers to obtain building permits as soon as one business day.

Similar to California state law, Mill Valley mandates that both detached and attached ADUs should be a minimum of 4 feet from the side and rear property line and 15 feet from the front property line.

Measured from outside walls, 1,000 square feet is the upper limit for two-bedroom ADUs in Mill Valley, while one-bedroom and studio units have a maximum of 850 sq. ft. In terms of height. Most detached ADUs can be up 16 feet with two exceptions:

  • The max for secondary units with a garage is 25 feet.

  • ADUs on multi-family properties have a height restriction of 18 feet.

In addition, junior ADUs (JADUs), which are a smaller version of standard ADUs, can be up to 500 sq ft. A primary residence located in a single-family zoning district can have a max of one ADU and one JADU.

Typical appliances found in an accessory dwelling unit may include:

  • Refrigerator

  • Oven

  • Dishwasher

  • Stove or cooktop

  • Microwave


For added comfort and convenience, many ADUs also have heating and cooling systems, water heaters, and an in-unit washer and dryer.

First, make sure your property zoning allows ADUs. Most Mill Valley residential areas with single-family homes do permit ADUs, but it’s worth checking with the city’s planning department, which can advise you on setback requirements, height restrictions, and square footage limits in respect to your lot size.

Then browse prefab ADU floor plans to find one that suits your needs. Options range from studio units to spacious two-bedroom designs. Consider how you’ll use the space—for example, as a home office, personal gym, or living space—to determine the right size and layout.

After you’ve selected a floor plan, obtain the proper permits from the city to build your new ADU. This usually involves submitting plans for review and paying permit fees.

Once the building permit is issued, prepare the site where your ADU will be installed by clearing space, leveling the ground, and installing utility connections. The ADU builder will begin constructing your prefab ADU, then deliver it when it’s ready.

After final inspections by the city, you can start enjoying your additional living space.

Learn more about Abodu Prefab ADUs

Unlock your property’s potential with a pre-approved Abodu ADU. Our team is here to provide comprehensive support with your prefab ADU project from start to finish. With our expertise and experience, we can handle every step of the building process, from permitting and construction to crane delivery of your timeless ADU.

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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.