Prefab ADU companies in California: published prices compared (2026)

How we built this list

We don't rank or recommend builders. Every price below comes from the company's own website as it read on October 27, 2026, and companies change prices often. Where a company didn't publish a price, we say so instead of filling the gap from news stories or review sites. The companies are listed alphabetically. Inclusion isn't an endorsement, and a company being absent says nothing about it.

“Prefab” covers several legal categories: modular units with a state insignia, HUD-code manufactured homes and panelized kits. Our guide to the prefab ADU in California explains how each is approved, and modular vs manufactured ADUs compares them on financing and foundations. If you have a garage, converting it is often cheaper than any factory unit; see our garage conversion ADU guide and the garage conversion cost breakdown. Looking smaller still? Read about the tiny home ADU.

Prefab ADU companies in California compared

Every figure in the table links to the company's own page. Plant Prefab, Connect Homes, Mighty Buildings and Villa are covered below, because we couldn't confirm a current published ADU offer for them.

Abodu ADU prices by model

Abodu's pricing page splits every model into a home price and an installation price. Per-square-foot figures are our arithmetic from those numbers.

The pattern holds across the industry: small units cost the most per square foot, because the kitchen, bath, foundation, utilities and permit cost about the same at any size.

Samara Backyard

Samara's Backyard page lists six models and a starting price of $152K “plus installation,” and says Backyard is available in California. Its FAQ says installation is priced per property and covers project management, permit allowances, surveys, utility connections, crane and traffic control, entry stairs and solar. It also says payments are spread across milestones and that it won't collect payment or start work until you've secured financing.

Studio Home (Studio Shed) ADU kits

Studio Home's ADU page (studioshed.com now redirects there) lists models such as the 490 sq ft Larch from $123,146 and the 618–682 sq ft Laurel from $143,100, each “+ installation.” The kits are panelized and ship flat-packed from Colorado for on-site assembly. A kit price is not a finished ADU: foundation, utilities, assembly, permits and fees come on top, and you'll need a licensed contractor to build it. For prefab ADU kits in general, our guide to Amazon and Home Depot tiny home kits covers what a kit leaves out.

Acton ADU

People often search for Acton ADU alongside prefab companies, but Acton's own site describes its homes as traditionally site-built, not prefab or mobile, and it is based in Campbell in the Bay Area. It publishes no prices.

What the published prices include, and what they don't

To compare quotes, line them up against one clearly itemized offer. Abodu lists what sits in and out of its price, which makes a useful checklist for any company:

Source: Abodu pricing, October 2026. On top of any company's quote, ask about items that depend on your lot. Snap ADU's San Diego sitework guide lists a separate SDG&E meter at $10,500–$15,000 and retaining walls at $20,000–$30,000+, and its fee table puts City of San Diego fees at $10,734 for a 499 sq ft ADU (a builder's figures, not official fees). Across turnkey prefab offers, Snap ADU's October 2026 survey found 800 sq ft two-bedroom units in California ran about $280K to $430K all-in. Snap ADU builds site-built ADUs, so read that as one builder's view.

For prefab ADU cost in context, see what an ADU costs in San Diego or try the ADU cost calculator.

Companies we couldn't confirm

Several well-known names don't have a current, published ADU offer we could verify. That doesn't mean they're closed; it means you should confirm directly before relying on an old article or listing.

• Connect Homes. As of October 2026, connect-homes.com redirects to Connect Shelters, which markets temporary and permanent modular housing and doesn't mention ADUs. We found no current published ADU price.
• Mighty Buildings. The Oakland 3D-printed prefab builder put itself up for sale in January 2025 and laid off a major portion of its staff, according to Fabbaloo. Its website didn't load when we checked. We couldn't confirm it takes ADU orders.
• Plant Prefab. Its website describes panelized and modular components for housing and hospitality projects, but publishes no ADU models or prices.
• Villa. We couldn't load a current published price on Villa's own website. Ask the company for its price list and what it includes.

Prefab ADUs in San Diego

Service areas matter as much as price. Abodu's FAQ says it serves California “generally in the San Francisco Bay Area and Greater Los Angeles Area”; it doesn't mention San Diego. Samara's FAQ names no service area. Ask any company whether it has installed units in your city and who does the local site work.

For a prefab ADU in San Diego, the unit comes from the factory but the foundation, trenching, utilities and permit are local work, often done by a local general contractor. You can compare verified ADU builders in San Diego who can install a factory unit or build on site, read our shortlist of the best ADU builders in San Diego, and see the steps for getting an ADU permit in San Diego.

How to vet a prefab ADU company

• Find the license, then check it. The Contractors State License Board says a B, General Building contractor can build or install ADUs, and a C-47 can install a manufactured-home ADU. Look up the exact company name on the state's Instant License Check or check a contractor's license on our site. If the seller isn't licensed, find out who holds the license for your site work.
• Ask what label the unit carries. A modular unit sold in California must carry an HCD insignia of approval; a manufactured home carries a HUD certification label on each section. A panelized kit may carry neither and is inspected by your city. Neither Boxabl's home page nor Studio Home's ADU page says directly whether it delivers in California, so ask.
• Know the deposit rule. On a home improvement contract, California law caps the down payment at $1,000 or 10% of the price, whichever is less, and bars payments ahead of completed work. A unit purchase agreement may be structured differently, so ask how much you'll have paid before the unit leaves the factory.
• Get one all-in number for your lot. Use the checklist above: trenching length, crane distance, survey, demolition, fees and meter.
• Visit an installed unit. A showroom shows finishes; a finished backyard project shows the site work.

For contracts, liens and payment schedules, read how to hire an ADU contractor, and our broader look at ADU companies.

When prefab companies fail

• Anchored Tiny Homes (Fair Oaks), which sold tiny homes and ADUs, closed in 2024. A former executive said 450 customers were left stranded; one customer reported losing a $28,000 payment.
• Multitaskr (Chula Vista) collapsed in 2024, and the average claim per ADU topped $200,000.
• Nonna Homes (Rancho Cordova) had its license suspended in January 2026.

All held or worked under contractor licenses. A license is the floor, not a guarantee; payment timing is your best protection.

Common questions