Costa Mesa, CA Accessory Structures: ADU Owner Occupancy (2026)
Key Facts
- Owner-occupancy applies to
- Junior ADUs only, not standard ADUs
- Owner may live in
- Either the primary home or the JADU
- Exempt owners
- Government agency, land trust, housing organization
- Enforcement mechanism
- Recorded covenant with county recorder
- Governing section
- Costa Mesa Municipal Code § 13-35(c)(3)
Summary
Costa Mesa requires the owner of a lot with a Junior ADU to live in either the primary home or the Junior ADU as a primary residence under Municipal Code § 13-35(c)(3). Standard ADUs carry no such owner-occupancy requirement; only Junior ADUs trigger it, with an exception for government agencies, land trusts, and housing organizations.
(3) Owner occupancy requirement. The owner of a parcel proposed for a Junior ADU shall occupy as a primary residence either the primary dwelling unit or the Junior ADU. Owner-occupancy is not required if the owner is a governmental agency, land trust, or "housing organization" as that term is defined in Government Code section 65589.5(k)(2), as that section may be amended from time to time.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4894290; v9 updated 2025-11-18).
Full Breakdown
' The owner isn't required to live in both, just one of the two units, and can move between them over time as long as one remains their primary residence. 5(k)(2). The rule is enforced through a recorded document: before final inspection and occupancy of a Junior ADU, the owner must file a covenant with the county recorder, in a form approved by the city attorney, that restricts the Junior ADU from being sold separately from the primary residence and confirms the JADU is 'legal only as long as either the primary residence or the JADU is occupied by the owner of record,' unless a government agency, land trust, or housing organization owns it.
That covenant also restricts the Junior ADU to the maximum size allowed under section 13-35 and binds successive owners of the property, so a buyer who purchases the home inherits the same occupancy obligation. Standard ADUs, by contrast, carry no owner-occupancy requirement anywhere in section 13-35, a distinction the city draws explicitly between the two unit types.
Violations & Fines
Failing to maintain owner occupancy of either the primary residence or the Junior ADU breaches the recorded covenant required by § 13-35(c)(3) and (d)(5), which can trigger legal action against the property owner under the covenant's own terms as well as prosecution as a zoning violation under § 13-16, punishable as an infraction (fines up to $500 for repeat offenses under § 1-33) or misdemeanor carrying up to $1,000 and six months in jail.
Frequently Asked Questions
Do I have to live in my house if I build a Junior ADU in Costa Mesa?
Does a standard ADU in Costa Mesa require owner occupancy?
Who is exempt from the Junior ADU owner-occupancy rule?
Sources & Official References
Other rules in Costa Mesa
California rules heatmap·Compare Costa Mesa to another location·View the California accessory structures overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.
ADU Owner Occupancy in Nearby Cities
How other cities in Orange County handle adu owner occupancy.