Permits
In Practice
A space built with a permit but never issued a CO is not legally habitable, even if construction appears complete. Occupying a space without a CO is a code violation. A surprisingly common situation is a homeowner who completes construction but allows the permit to lapse before obtaining the final inspection and CO — resolving a missing CO after the fact is more complex and costly than obtaining it in the normal course. For ADUs intended for rental, the CO is also a prerequisite for legal rental occupancy.
Source: How to Apply for a Building Permit: Step-by-Step Guide · Verified April 5, 2026