Accessory dwelling units adus — 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
ADUs are secondary homes on a single-family lot that provide independent living facilities. You might consider an ADU if you want to increase your property value or provide housing for family. These units are versatile and can be detached or attached to the main house. Exact pricing confirmed free on the call.
Frequently asked in Costa Mesa
What does 'adu unit' mean for my Costa Mesa property?
An 'ADU unit' means adding a secondary, independent living space to your existing property in Costa Mesa. This could be a detached structure like a backyard cottage or an attached unit within your current home. It's designed for someone to live in, complete with its own kitchen, bathroom, and sleeping area. We help you understand its potential.
What are the costs for accessory dwelling unit construction in Costa Mesa?
Are there specific ADU companies to choose from in Costa Mesa?
What is the cost of an accessory dwelling unit in Costa Mesa?
The cost of an accessory dwelling unit in Costa Mesa depends on its size, design, and the materials selected. Factors such as site preparation, foundation requirements, and utility connections also play a significant role in the final price. To get an accurate estimate for your specific project, it's best to obtain a personalized quote. We can help arrange that.
What are the steps for accessory dwelling unit construction in Costa Mesa?
What is a modular accessory dwelling unit?
What are the permit requirements for an ADU 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 del Mar, The Heights, Westside Costa Mesa, Eastside Costa Mesa, South Coast Metro — and every surrounding area.
Areas we serve
Browse by state, then city.
California (3)
All of California · Costa Mesa · Jurupa Valley · Santa Maria