Costa Mesa describes a local process for accessory dwelling units (ADUs) and junior ADUs (JADUs) built without permits before January 1, 2020. Its guidance presents date evidence, plan review, permits and inspection as separate steps. A qualifying construction date is only one part of the process; the City must review the particular site, plans and safety conditions.
Consider an early review, but do not treat it as approval
Before submitting a permit application, an owner may hire a licensed contractor for a confidential third-party code inspection. Costa Mesa says this is an optional way to understand the unit’s condition and likely scope of improvements; the report is informational and need not be submitted to the City. The City also describes an optional pre-application inspection by City staff. Neither early review legalizes the unit or guarantees that the later permit will be approved.
The City’s application checklist asks for information such as the parcel and address, floor plans, evidence of the construction date, dimensions and setbacks, access and parking, utility locations, and site hazards. Planning, Building, Public Works, Fire and outside agencies may review the plans for safety compliance. Confirm the current checklist and required agencies with the City because the review depends on the location and characteristics of the unit.
Permits come before corrective construction
Costa Mesa states that it issues permits after plan review and payment of applicable fees. If the review identifies safety corrections requiring construction, that work follows permit issuance and is then checked through required inspections. An unpermitted unit should not be described as legalized simply because an owner obtained a private report, attended a consultation or submitted an application. The final status depends on the permits and inspections required for the property.
Use the City’s Safe ADU Legalization Program page for current application steps and forms. Ask Costa Mesa which record closes the process and compare that record with the work actually completed. For context on why hidden work can lead to additional inspection or corrections, see corrective work for an existing ADU.