Costa Mesa
Why Invest in Costa Mesa for ADU’s?
Costa Mesa is one of Orange County’s most sought‑after “urban‑suburban” coastal cities, with residential streets just minutes from the beach and major freeways. The demand for housing is extremely strong, which leads to high rents, low vacancy, and steady long‑term growth in value for well‑located properties.
For investors, Costa Mesa’s higher home prices can actually help when you add an ADU. In a cheaper city, the same $360K ADU may only add a little equity because homes sell for less per square foot; in Costa Mesa, that same ADU is significantly more on the resale value since prices per square foot are higher when reselling, so each new unit you build can create more equity and strong ADU rent.
Costa Mesa ADU Requirements
Detached ADU
One of Costa Mesa's strongest cash-flowing ADU options is a detached Accessory Dwelling Unit, generating $3,900–$4,500/mo. East side Costa Mesa commands the higher end due to its rental desirability and proximity to Newport Beach. West side Costa Mesa sits at the lower end — however, west side has been rapidly developing, making it an increasingly attractive entry point for investors.
A detached ADU can be up to 1,200 sq ft, large enough for a full 3 bed / 2 bath layout.
Setbacks
6 ft from the main house
4 ft from side and rear property lines
Front yard follows standard zoning rules
Junior ADU (JADU)
A Junior ADU is one of the most cost-effective ways to add rental income in Costa Mesa, generating $2,200–$2,500/mo. Because it's built within the existing home's footprint — no new foundation, no major addition — it's typically the faster and cheaper path to a second income stream on the same lot.
Best suited as a studio or compact 1-bedroom with its own entrance and kitchenette. East side Costa Mesa will command the higher end of that range, with west side coming in closer to $2,200.
Key Rules
Maximum 500 sq ft which can fit a studio or 1 bedroom
No owner-occupancy requirement: change as of 2025 with AB 1154
