ADU Construction in Costa Mesa
Serving 92626 · 92627 and Newport Beach, Huntington Beach, Santa Ana
Costa Mesa has the combination that makes accessory dwelling units work: original houses that are small relative to their parcels, rear yards with genuine space left, and no coastal zone review. Where a lot has real room behind the house, a detached unit is frequently a better use of budget than reshaping the existing footprint.
Why so many Costa Mesa ADUs pencil
What the checks actually are
Setbacks, existing lot coverage, construction access and the run for water, waste and power. Those four decide most schemes long before anything aesthetic does.
State law and the city ordinance together
State ADU law sets the floor for what must be permitted; the city applies its own ordinance alongside it. Both are read against the specific parcel — we do not assume a rule applies without checking it.
Written by Onn Cohen-Meguri, founder and designer at Design Onn Point. Onn has spent 20+ years designing and building in Los Angeles. CSLB #1133368.
Pricing in Costa Mesa
Market estimate, not our own project data.
Talk to Onn about your Costa Mesa adu construction.
Free consult, no obligation. Onn reads every inquiry personally — and aims to reply within one business day.
From the blog
ADU vs Garage Conversion: Which Adds More Value in LA?
Side-by-side comparison of detached ADUs and garage conversions for LA homeowners — costs, timelines, ROI, rental income, and which one adds more value on resale.
LA County Kitchen Permits Explained (2026 Edition)
When you need a permit for an LA kitchen remodel, how LADBS plan-check works, typical timelines, and how to avoid the common mistakes.