Adu construction — 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
Frequently asked in Costa Mesa
What ADU housing options are available in Costa Mesa?
Is emergency ADU construction a service that exists?
What is the typical ADU cost in Costa Mesa?
How much does an accessory dwelling unit cost to build?
Where can I find an accessory dwelling unit near me in Costa Mesa?
What accessory dwelling unit services are offered?
Can I get a modular accessory dwelling unit 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, Mesa Del Mar, South Coast Metro, The Mesa, Fairview Shores — and every surrounding area.
Areas we serve
Browse by state, then city.
California (3)
All of California · Costa Mesa · Jurupa Valley · Santa Maria