At California Modular Houses, we help homeowners build high-quality prefab modular homes and modular ADUs to California residential building codes.

From floor plans and customization to preliminary permitting guidance and project coordination, our team simplifies the modular home process throughout California.

We make building new homes & ADUs easy.

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Start Your Modular Project Here

If you would like pricing, specifications, want to share details about your project, design ideas, or the permitting process:

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Privacy Policy (we don’t sell your information to anyone, it’s kept confidential)

Featured Ruby Series

View Ruby ADU Modular Plans

ADU Floor plans California, Prefab ADU California, Prefab Modular Accessory Dwelling Unit, Prefab Modular ADU CA. The Sweet Acacia ADU Model of 1106 Square Feet

$$ - Lowest Overall Pricing

Efficient modular homes and ADUs with smaller footprints and lower overall project costs.

View Ruby Full-Sized Modular Plans

The Lake Almanor Modular Home of 1,552 SF. 3 Bedrooms & 2 Bathrooms. Modular Floor plans California, Prefab Modular California, Prefab Modular Home, Prefab Modular House CA.

Best value full-sized homes we offer.

Customizable Platinum Series

$$$ - Best Overall Value

View ADU Modular Plans

Prefab modular ADU, ranch style home built in Sebastopol, Sonoma County, California by California Modular Houses.

$$$$ - Lowest Platinum Pricing

The lowest priced modular homes of this collection. Less than 1200 square feet.

View 1200-2000 SF Modular Plans

Prefab modular single-family-residence, white, lap and horizontal siding built in Santa Rosa, Sonoma County, California.

$$$$ - Best Platinum Value

Our most popular modular homes, designed for value, efficient installation, & compatibility with many properties.

View Hollywood Modular Plans

Luxury style prefab modular home, gray siding and blue door, dormer windows.

$$$$ - Very Good Value

Flexible multi-section modular homes that balance space, efficiency, & functionality.

View 2000+ SF Modular Plans

Prefab modular, rustic cabin style home built in Crescent City, Del Norte County, California. Blue and brown themed.

$$$$ - Very Good Value

Spacious modular home layouts that offer excellent value per square foot for larger living spaces.

View Two-Story Modular Plans

Green siding and brown trim, prefab modular two-story home in Carpinteria, Santa Barbara County, California.

$$$$$ - Good Value

Two-story modular homes maximize living space and work well for many property types and site conditions.

SPECIAL PRICING DISCOUNT

Please provide us with the property address of where you are building your home and we will happily provide you with a quote including transportation and the full specifications for the home.  

Contact Us

THE WATER BIRCH

ADU

$209,354

862 SF

2

Line drawing of a bed with a headboard and pillow. ADU Floor plans California, Prefab ADU California, Prefab Modular Accessory Dwelling Unit, Prefab Modular ADU CA.

1

A bathtub filled with bubbles and soap suds, with bubbles rising above it. ADU Floor plans California, Prefab ADU California, Prefab Modular Accessory Dwelling Unit, Prefab Modular ADU CA. The Sweet Acacia ADU Model of 1106 Square Feet

Temporary Discount $2,000

Explore The Water Birch, 696 sq ft single story prefab modular ADU floor plan for California, 2 bedrooms, 1 bathrooms with, site built porch, open concept kitchen, & energy-efficient prefab construction. Accessory Dwelling Unit California

THE LANIKAI

SFR WITH ATTACHED ADU

$369,844

1991 SF

4

ADU Floor plans California, Prefab ADU California, Prefab Modular Accessory Dwelling Unit, Prefab Modular ADU CA.

3

Line drawing of a bathtub filled with bubbles and soap, with bubbles rising from it. Modular Floor plans California, Prefab Modular California, Prefab Modular Home, Prefab Modular House CA.

Special Pricing Ends on 07/31/2026

Architectural blueprint of a single-story house with a front elevation view, featuring a two-car garage on the left. Modular Floor plans California, Prefab Modular California, Prefab Modular Home, Prefab Modular House CA.

Discount Terms & Conditions:

Discount is offered on a limited time basis and is subject to change prior to the signing of a complete purchase agreement.

Factory Built Home Pricing:

The stated pricing is the price of the modular home with our standard specifications, ready to ship from the factory. A shipping allowance is required for transportation to the property or mutually designated location (usually the closest County maintained road). A final quote for transportation will be provided upon the scheduling of the transportation, depending upon fuel prices, road conditions, etc.

On-Site Work (by Others):

California Modular Houses, Inc. is not a construction company. We focus on Design, the Plans for the Factory Built Home, Coordination with other required professionals, working with you on the specifications for your home, the order of the home itself, and then delivery. On-site work is not performed by California Modular Houses, Inc. and we aren’t able to estimate the cost of the on-site work.

The on-site work is to be priced out by a California Licensed General Contractor (Others) once there is a full set of plans in hand. Preliminary pricing from a contractor that does not have a full set of plans is guesswork. The contractor needs to have plans that show everything that is desired and required for the project in order to provide a firm quote. We can introduce you to a contractor when you get to that point or you can also interview local contractors to make sure you are getting the best contractor and value for your project.

What We Build & What We Don’t

A house with a gray exterior, white garage door, and a porch with a small garden. The front yard includes cacti and lush green plants, beneath a clear blue sky.
For more information, click here.

California Modular Houses builds "Factory Built Housing" which is the technical term. In the industry we call them "Modular" homes for simplicity sake. They are often referred to by consumers as "Prefab Homes" though that term is broad and doesn't specify what building code the home is built to. All of our homes are built to the California Building Code, the same building code that a site built home is built to.  

We do not build or sell Manufactured, Mobile, or Trailer homes. Those are build to the HUD which is a federal code for people that require low cost living accommodations.

Our gallery has hundreds of images of our completed prefab modular homes.

Take a look and contact us for more info.

Click to visit our gallery to view our homes, from start to finish.
Prefab Accessory Dwelling Unit. Modular Homes. Modulars for City of Santa Cruz, Santa Cruz County, CA. Pre-fabricated homes. Prefab ADU models. California prefab ADU. Modular. Prefab ADU California.
A brand prefab modular home placed on top of a walk-out basement concrete foundation. The garage was built on-site after the home was placed on the foundation. Modular CA. Modular Prefab in Santa Rosa, CA. Sonoma County.
White and gray Cape Cod style home built in Mendocino, Mendocino County CA designed by California Modular Houses, Inc.
Sage green home with white trim, cherry red door built in Pinole, Contra Costa County, CA designed by California Modular Houses, Inc.
This modular Cape Cod was built in Lafayette, Contra Costa County, California. Prefab Modular CA. Modulars for the California Bay Area. Unfinished Attic.
Brown cabin style home with green trim and large full wall transom windows designed by California Modular Houses, Inc.
New Custom Modular home for City of San Mateo, San Mateo County, CA. This prefab home was built in California in the San Francisco Bay Area. Modulars. Homes. New Single Family Residence. CA Modular Home. SFR.
A modern white house with a gray roof, illuminated from within, featuring a small front porch, a black front door, large windows, and an attached garage. The house is surrounded by a white picket fence and landscaping including bushes and roses, with
Here are two homes that we built after the loss of the original homes in a fire. Both of these homes are each a Prefab Modular Home. Modular Homes in Calistoga, CA. Modulars Napa County, California
Modular. Prefab ADU California. California prefab ADU. Prefab Accessory Dwelling Unit. Modular Homes. Modulars for Sebastopol, Sonoma County, CA. Pre-fabricated homes. Prefab ADU models.
Modern single-story house featuring a porch with multiple columns and stone accents. New Modular home for Gustine, Merced County, CA. This prefab home was built in the California Central Valley. Modulars. Homes. New customized modular.
Sage green, brown trim on a prefab modular two-story home built in Carpinteria, Alameda County, CA designed by California Modular Houses, Inc.
The Teal Modular. Prefab ADU California. California prefab ADU. Prefab Accessory Dwelling Unit. Modular Homes. Modulars for Martinez, Contra Costa County, CA. Pre-fabricated homes. Prefab ADU models.
Logo of the National Association of Home Builders, NAHB, and the full name below, featuring red, blue, and beige colors. This is part of the NAHB, the National Association of Home Builders and available only to members in good standing.
Logo of the California Building Industry Association featuring stylized buildings and text. This is part of the NAHB, the National Association of Home Builders and available only to members in good standing.

WE ARE HONORED TO BE MEMBERS OF:

BBB Accredited Business logo with blue flame symbol and text. We are a Better Business Bureau Accredited Company in California. Prefab Modular. Modular California. Prefab California.
Logo of the American Institute of Building Design featuring the word 'MEMBER' at the top. This is only available to verified designers of homes in good standing with the AIBD.
Logo of the San Francisco Bay Area Building Industry Association with green and black text. Available only to members of the NABH - The National Association of Home Builders.

The Modular Building Process, Simplified

  • Vacant property, one of the starting points of every new single family house building project. Modular Home Building for California.

    Property & Planning

    Start with your land and your goals. We help you understand zoning, site conditions, and budget considerations so you can choose the right modular home.

  • Modular floor plan of a house showing various rooms and dimensions, including bedrooms, bathrooms, living room, kitchen, utility room, garage, and porch.

    Design & Feasibility

    Select a floor plan and confirm what can be delivered to your property. Plans can be stock, customized, or fully designed to fit your needs.

  • Large truck with 'OVERSIZE LOAD' on the front is on a narrow, winding forested road, with trees and branches on both sides. Several workers wearing safety vests are inspecting the situation and verifying that the home is delivered safely.

    Permits & Prep

    Engineering and plans are completed, permits are submitted, and your site is prepared for construction with experienced modular professionals.

  • Modular Prefab California Home: Front view of a modern house with a brick porch, white siding, multiple large windows, and a small front yard with gravel and plants.

    Build & Move In

    Your home is built in the factory while site work happens simultaneously, then delivered, assembled, inspected, and ready for you to move in.

Schedule a Modular Feasibility Study With Us

Modular Home FAQs

Some of the most commonly asked questions regarding modular homes.

Check out our Modular Home FAQ page to read these answers in depth.

Modular Homes FAQs

  • Modular homes are real single-family homes built to the California Residential Code, just like traditional site-built homes. Unlike manufactured or mobile homes, modular homes are factory-built in sections and assembled on-site on a permanent foundation. They are financed, appraised, and valued similarly to conventional homes.

  • Modular homes can offer faster build times, better cost control, and a more streamlined building process compared to traditional site-built homes. Using proven floor plans also helps reduce stress, simplify planning, and provide clearer pricing earlier in the project.

  • Modular homes are real single-family homes built to the California Residential Code, just like traditional site-built homes. Unlike manufactured or mobile homes, modular homes are factory-built in sections and assembled on-site on a permanent foundation. They are financed, appraised, and valued similarly to conventional homes.

  • Choosing a stock modular home plan is usually the fastest and most cost-effective option. Pre-designed plans help simplify engineering, speed up the process, and reduce overall project costs.

Featured Plans by our Designer

Prefab Modular Homes Designed by our Designer

Please provide us with the property address of where you are building your home and we will happily provide you with a quote including transportation and the full specifications for the home.  

Contact Us

ADU of the Month

THE DESERT WILLOW

$220,019

RUBY SPECIFICATIONS

750 SF

2

Line drawing of a bed with a headboard, pillow, and blanket. Modular Floor plans California, Prefab Modular California, Prefab Modular Home, Prefab Modular House CA.

1

ADU Floor plans California, Prefab ADU California, Prefab Modular Accessory Dwelling Unit, Prefab Modular ADU CA. A bathtub filled with bubbles and soap bubbles floating above.

Temporary Discount $2,000

Explore The Desert Willow, 750 sq ft single story prefab modular ADU floor plan for California, 2 bedrooms, 1 bathrooms with, site built porch, open concept kitchen, & energy-efficient prefab construction. Accessory Dwelling Unit California

Home of the Month

THE LAKE ALMANOR

$355,972

RUBY SPECIFICATIONS

1552 SF

3

A bathtub filled with bubbles and floating soaps and toys. ADU Floor plans California Prefab ADU California

2

Outline of a bed with a pillow and headboard. ADU Floor plans California, Prefab ADU California, Prefab Modular Accessory Dwelling Unit, Prefab Modular ADU CA.

Temporary Discount $3,500

Modular Floor plans California, Prefab Modular California, Prefab Modular Home, Prefab Modular House CA. The Ruby Series: The Lake Almanor Modular home.

Tour The Jay,

Prefab Modular ADU

After working together for several years on multiple projects, these clients trusted us with building their own ADU. As modular project managers with over 30 years of experience, we ensure a home to be proud to live in.

Visit our YouTube Channel for more videos, including renderings that our in-house designer will complete for you through our Drafting Services.