ADU Contractors in California
Nestadu
100 Shoreline Highway, Mill Valley, CA 94941
Nestadu is a full-service ADU builder offering custom site-built and prefab accessory dwelling units. Prefab models range from $115K–$317K. Custom builds start at $400/sq ft. Financing options include HELOCs, construction loans, and CA grants.
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Custom Home
2092 Concourse Drive, San Jose, CA 95131
Custom Home is a Bay Area ADU contractor (CSLB #986048) with 160+ projects since 2005. They build detached, attached, junior ADUs & garage conversions across South Bay & Peninsula, with costs from $120K–$500K+.
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Downey ADU Builders
8607 Imperial Highway, Downey, CA 90242
Downey ADU Builders offers expert ADU contractor services including detached ADUs, garage conversions, attached ADUs, JADUs, and home additions. Licensed contractors handle permits, design, and construction with 10+ years of experience.
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Bay Builders & Remodeling
800 Charcot Avenue, San Jose, CA 95131
Bay Builders & Remodeling specializes in custom ADU construction across Santa Clara, San Mateo, and East Bay. Services include attached, detached, garage conversions, and JADUs, helping homeowners add rental income, family housing, or workspace.
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Edri Construction, Inc. San Francisco
701 Cortland Avenue, San Francisco, CA 94110
Edri Construction, Inc. is a San Francisco-based ADU contractor offering full-service accessory dwelling unit construction across the Bay Area, including garage conversions, detached ADUs, granny flats, and energy-efficient home additions with in-house project management.
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GLAD Construction ADU Builders
3600 Madison Avenue, North Highlands, CA 95660
California offers ADU funding via CalHome, LEAP, LHTF, REAP, SB 2 grants & CDBG. Local programs in San Diego, San Jose & more aid homeowners. GLAD Construction ADU Builders guides projects from permits to completion.
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Aboveboard Construction
3950 Bramble Lane, Santa Cruz, CA 95062
Aboveboard Construction Inc. serves Santa Cruz County & Los Gatos with 20+ years in residential construction. Services include new homes, ADUs, remodels, additions, kitchens, bathrooms, decking, fencing & repairs.
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USA Builders Pro
2900 Bristol Street, Costa Mesa, CA 92626
USA Builders Pro offers 20+ years of ADU construction and home addition services. Specializing in detached & attached ADUs, room additions, permits, and zoning compliance, they help homeowners boost property value and living space.
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Temecula ADU Builders
45033 Putting Green Court, Temecula, CA 92592
Temecula ADU Builders is a local ADU contractor helping homeowners add accessory dwelling units, including detached ADUs, garage conversions, and granny flats, for rental income, family housing, or tax benefits in Temecula, CA.
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Tiny Home Associates
740 Hilltop Drive, Chula Vista, CA 91911
Veteran-owned US ADU & tiny home builder serving San Diego & LA County. Premium materials, ANSI A119.5-compliant builds, Class A fire ratings, 3D design, site assessment, permitting support & NOAH/RVIA certification included.
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Morrison Construction
601 Carmen Dr, #215D, Camarillo, CA 93010
Morrison Construction offers expert ADU building services in West Hills, handling everything from planning to completion. Services include custom design, construction, plumbing, electrical, and interior finishes for granny flats, rental units, and in-law suites.
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Herbertson OG
6306 DOWNEY St, Riverside, CA 92509
Herbertson OG is a construction and solar company offering ADU building, remodeling, new construction, roofing, HVAC, and solar panel installation. They serve homeowners, investors, and designers across residential and commercial projects.
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ModernSpace ADU Construction Chula Vista
330 Oxford Street, Chula Vista, CA 91911
ModernSpace ADU Construction is a trusted ADU builder in Chula Vista offering detached ADUs, granny flats, garage conversions & in-law suites. Free consultations, upfront quotes, quality craftsmanship & full satisfaction guaranteed.
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Custom ADU Builder
113 West Santa Fe Avenue, Fullerton, CA 92832
Full-service ADU contractor offering design, permitting, and construction of detached ADUs, attached ADUs, JADUs, and garage conversions. Most builds complete in 3–5 months. Includes quartz countertops, tile showers, and luxury vinyl flooring. Rental prep support available.
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The Avalon Comany
3911 N Cordoba Ave Suite 6, Spring Valley, CA 91977
Homeowners across the San Diego area looking to expand their living space or create a rental opportunity turn to the trusted San Diego Builders at The Avalon Company. With more than three decades of experience, they specialize in designing and constructing high end accessory dwelling units that blend seamlessly with your existing property while increasing functionality and property value.
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Other cities in California
What you need to know
ADU Contractors in California: Navigating the Golden State's Unique Landscape
California is at the forefront of the Accessory Dwelling Unit (ADU) movement in the United States. With one of the most severe housing shortages in the nation, the state has enacted sweeping legislation to make ADU construction more accessible. Since 2020, California laws such as AB 68, AB 881, and SB 13 have significantly reduced barriers, eliminating minimum lot size requirements, reducing setback rules, and streamlining the permitting process. For homeowners looking to add value to their property or create additional rental income, working with experienced ADU contractors in California has never been more important.
What California ADU Contractors Must Know About State Regulations
Professional ADU contractors operating in California must stay current with a constantly evolving regulatory environment. Under California law, local agencies are required to approve or deny ADU permit applications within 60 days. Additionally, ADUs under 800 square feet cannot be denied solely based on floor area ratio limits. Contractors must also be familiar with owner-occupancy rules, utility connection requirements, and fire safety standards that vary by county and municipality. Cities like Los Angeles, San Diego, and San Jose each have their own local ordinances layered on top of state law, making local expertise a critical asset.
Types of ADUs Built by California Contractors
Experienced California ADU contractors are skilled in building a wide variety of ADU types to suit different property configurations and homeowner needs. The most common types include:
- Detached ADUs: Standalone structures built in the backyard or side yard of a primary residence.
- Attached ADUs: Units that share a wall with the main home, often built as additions.
- Garage Conversions: Transforming existing garages into livable spaces, a popular and cost-effective option.
- Junior ADUs (JADUs): Units up to 500 square feet created within the existing footprint of a home.
How to Choose the Right ADU Contractor in California
Selecting the right contractor is one of the most critical decisions in any ADU project. Homeowners should look for contractors who hold a valid California Contractors State License Board (CSLB) license, ideally a Class B General Building Contractor license. It is also important to verify that the contractor carries proper liability insurance and workers' compensation coverage. Look for professionals with a proven track record of successfully permitted ADU projects in your specific city or county.
The Benefits of Building an ADU in California
Building an ADU in California offers significant financial and lifestyle benefits. Homeowners can generate rental income to offset mortgage costs, house family members, or increase overall property value. In high-cost markets like the San Francisco Bay Area or Los Angeles, a well-built ADU can add hundreds of thousands of dollars in property value. With the right California ADU contractor by your side, the process can be smooth, compliant, and highly rewarding.