Prefabricated accessory dwelling unit — Costa Mesa, CA
Last updated: September 24, 2026
What affects the price
Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.
About this service
A prefab ADU is built in a factory and then transported to your property for final assembly. You might choose this if you want a faster construction timeline and less mess in your backyard compared to a traditional build. Because the structure is made off-site, it often helps with site control and weather-related delays. Exact pricing confirmed free on the call.
Frequently asked in Costa Mesa
What is an ADU company in Costa Mesa?
What does ADU construction entail in Costa Mesa?
Where can I find accessory dwelling unit builders in Costa Mesa?
What is the cost to build an accessory dwelling unit in Costa Mesa?
What are 'accessory dwelling units ADUs'?
'Accessory dwelling units' (ADUs) are secondary, independent living spaces built on a single-family residential lot. They typically include their own kitchen, bathroom, and entrance. ADUs can be attached to the main home or be a detached structure, offering flexibility for housing needs like rental income or accommodating family members.
What does 'adu near me' mean for someone in Costa Mesa?
What kind of accessory dwelling unit rental opportunities exist in Costa Mesa?
Also serving nearby: Santa Ana · Huntington Beach · Westminster · Irvine · Garden Grove
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Costa Mesa — population 108,354; about 6,855 residents per square mile across 15.8 sq mi. ZIP codes covered include 92626, 92627, 92628.
Neighborhoods served in Costa Mesa: Mesa North, Eastside, Mesa Del Mar, South Coast Metro, Westside — and every surrounding area.
Areas we serve
Browse by state, then city.
California (3)
All of California · Costa Mesa · Jurupa Valley · Santa Maria