Costa Mesa ADU Market Update – June 2026
Costa Mesa is one of the most active ADU markets in Orange County right now — and June's data makes it clear why both buyers and sellers keep watching it closely. The price points run wide, the neighborhood segments behave very differently from each other, and the right ADU configuration can mean the difference between a deal that sits and one that goes under contract in a week.
Here's what's live and what's closed in Costa Mesa right now, with the actual comp data behind each one.
What's Active Right Now
1198 Dorset Ln — $1,399,900 | 92626 | Active
A 5-bed/3-bath, 1,962 sq ft home on a 6,365 sq ft lot in a quiet cul-de-sac near Paularino Elementary. The ADU here is a Junior ADU — 385 sq ft on the upper level with its own private stairway entrance, deck, studio bedroom/living room, ¾ bath, and kitchenette. Separate address. Currently vacant and unrented.
At $1,399,900 ($713/sq ft), this is the most attainable entry point in the current Costa Mesa ADU market. The JADU can generate rental income — market rent for a furnished upper-level unit with private entry in this pocket runs roughly $1,800–$2,200/month — but buyers need to know that Costa Mesa prohibits short-term rentals, so any income strategy here has to work on a long-term lease. This is a trust sale, listed fresh as of 6/19/26.
2782 Mendoza Dr — $2,325,000 | 92626 | Active Under Contract
This one's already under contract — after just 7 days on market. A 4-bed/3-bath, 2,014 sq ft single-story home in the sought-after Mesa Del Mar neighborhood, with a newly completed 499 sq ft detached ADU built in 2026 with city permits. Separate electric meter on the ADU. The main home is fully updated — quartz counters, remodeled kitchen, and a T-shaped lot with multiple outdoor living spaces including an outdoor fireplace patio, stone pavers, built-in BBQ, and beverage cooler.
Seven days to contract at $2,325,000 is the signal here. Mesa Del Mar is a premium pocket and this ADU was brand new. Buyers didn't hesitate. At $1,154/sq ft on the main home, this is also one of the highest price-per-foot sales in the Mesa Del Mar pocket recently — the new detached ADU did meaningful work in that pricing.
What's Closed
934 Governor St — Listed $1,290,000 / Closed $1,400,000 | 92627 | Closed 4/15/26
This one is the standout in this comp set. A 2-bed/3-bath, 1,848 sq ft home in Southwest Costa Mesa with approved plans and permits already in hand for a planned 590 sq ft ADU (1 bed/1 bath, separate meters). The house went under contract in 12 days and sold for $110,000 over asking — cash buyer, no concessions.
The key here is that the ADU wasn't built yet — just permitted and approved. The buyer paid $110K over list for the optionality of a city-approved, permit-ready ADU on top of a livable home. That's a real signal about how Costa Mesa buyers underwrite permitted ADU potential: they're pricing it as a built unit even when the concrete hasn't been poured. How appraisers actually support ADU value on a financed deal explains exactly why permit status matters so much at this step — and why unpermitted units don't get the same treatment.
212 E 19th St — Listed $2,995,000 / Closed $2,915,000 | 92627 | Closed 6/1/26
A premium Eastside Costa Mesa dual-residence play — 5 bed/4 bath, 2,578 sq ft on an 8,100 sq ft lot — with a fully detached 938 sq ft ADU built in 2025 (2 bed/2 bath, full kitchen, separate entrance, private patio). Designed and built by local firm Abode Design + Build. Took 90 days to close, sold $80K under its original $3,095,000 list price.
This is the Eastside premium: bigger lot, larger detached ADU, luxury finishes throughout. At $2,915,000, it's the top of the current Costa Mesa ADU market. The 90-day DOM is a reminder that even strong product at this price point requires the right buyer — design-forward, patient, coastal. Not everything at the top end moves in a week.
What the Numbers Are Telling Us
A few things stand out when you look at all four properties together.
Price range is wide — and it's driven by ADU type. From the $1.4M JADU entry to the $2.9M detached two-bedroom unit, Costa Mesa's ADU market spans nearly $1.5M in price. The ADU configuration — Junior vs. standard, attached vs. detached, new vs. planned — does heavy lifting in where any specific property lands in that range. How a home with an ADU is valued when you sell comes down largely to whether the appraiser can apply the income approach — which is only available on permitted units.
Permitted ADUs move markets faster. The Governor St property sold $110K over asking on the strength of approved plans alone. The Mendoza Dr property with a new 2026-built detached ADU went under contract in 7 days. Unpermitted units don't get that treatment — and Costa Mesa buyers are sophisticated enough to underwrite the difference. If you're evaluating a property with an unpermitted ADU, the pricing logic is meaningfully different and so is your buyer pool.
Eastside properties have more runway — and more patience required. The 19th St property sat 90 days before closing, which is long by current Orange County standards. Eastside Costa Mesa commands a real premium for lot size, neighborhood quality, and proximity to the coast — but the buyer pool at $2.9M is narrower. Those properties are also where large detached ADUs (900+ sq ft, two bedrooms) tend to show up, because the lots can accommodate them.
Costa Mesa prohibits short-term rentals. Any ADU income strategy in Costa Mesa has to work on a long-term basis — the city's short-term rental ban takes the Airbnb math off the table entirely. For a new 499 sq ft detached ADU in Mesa Del Mar, you're looking at roughly $2,200–$2,600/month long-term. For a 938 sq ft two-bedroom unit in Eastside, closer to $3,000–$3,500/month. Those numbers are still strong — they're just not inflated short-term rates. How lenders count that rental income when you're qualifying for a mortgage is a separate question worth understanding before you write an offer.
How Costa Mesa Compares to Nearby Markets
For buyers looking across Orange County, Costa Mesa currently prices higher than Garden Grove and Anaheim for similar ADU configurations — but with a different land basis and a different buyer profile. A new detached ADU deal in Anaheim might run $900K–$1.1M; the equivalent Mesa Del Mar deal is $2.3M+. The income math is different, but so is the appreciation story.
If you're more focused on cash flow than asset quality, Garden Grove or the Long Beach corridor are going to pencil more easily at current rates. If you're buying in Costa Mesa, you're buying for the land, the neighborhood, and the long-term value trajectory — not just the monthly rent check.
Under California's state ADU law, Costa Mesa homeowners have expanded flexibility to add units — including JADUs, detached ADUs, and conversions — and the city's own permitting process has become more predictable in recent years. Buyers who move quickly on well-positioned, permitted ADU properties are the ones capturing the premiums this data reflects.
Thinking About Selling an ADU Property in Costa Mesa?
The comps above show that the right Costa Mesa ADU property, properly positioned, can attract premiums and fast contract times. But the spread is wide — and how your ADU is characterized in the listing, how it appraises, and who sees the property all affect your outcome.
If you're considering a sale, download the free ADU Seller Kit or schedule a seller consultation before you list.
Data from CRMLS. Active/closed status as of 6/23/2026. Market data should be independently verified. This is not financial or legal advice.
