Accessory dwelling unit permit — 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
An accessory dwelling unit permit is the official authorization from your local municipality required to build a backyard home. You need this to verify that your project follows height, setback, and safety regulations. Navigating this process is a mandatory step that keeps your property compliant and insurable. Exact pricing confirmed free on the call.
Frequently asked in Costa Mesa
What is a prefabricated accessory dwelling unit in Costa Mesa?
What are accessory dwelling units (ADUs) in Costa Mesa?
Where can I find an ADU builder in Costa Mesa?
Where can I find an ADU near me in Costa Mesa?
What's an affordable accessory dwelling unit in Costa Mesa?
What's the best ADU for my property in Costa Mesa?
Can I get an ADU estimate 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 Verde, South Coast Metro, Fairview Shores, Upper Newport Bay, Westside Costa Mesa — and every surrounding area.
Areas we serve
Browse by state, then city.
California (3)
All of California · Costa Mesa · Jurupa Valley · Santa Maria