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.
Real projects. Real prices.
73 finished remodels published with their final price — nothing hidden.
What our finished LA work actually cost: 27 kitchens ran $23k–$84k, median $50k; 28 bathrooms $28k–$105k, median $38k; 17 whole-home remodels $36k–$440k, median $150k. Real final prices from our own job records, not estimates.
$30,000 A deep navy wall over textured white tile, with a floating walnut vanity and matte black fittings.
$37,000 A navy shaker vanity run with brass fittings, and a freestanding tub beside a see-through fireplace.
$38,000 Emerald shaker cabinetry and brass hardware around a cream range and an apron sink.
$75,000 Wood shaker cabinetry under a full-height quartz slab, with a marble-look hall bath.
$238,000 A walnut-fronted quartz island, arched openings, and sage-green stacked tile baths.
$275,000 A broad quartz island, a curved staircase with iron balusters, marble-look baths.
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 — 12+ years in business, 1,200+ finished Los Angeles projects. 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.