Certificate of Occupancy vs. Building Permit: What's the Difference?

A building permit is issued before construction begins and authorizes the work described in the approved drawings. A certificate of occupancy is issued after construction is complete and confirms the finished building meets code and is legally safe to occupy. You need the first to start; you need the second to actually move in, open for business, sell, or lease.

Between permit issuance and the CO, the project goes through a series of scheduled inspections tied to construction milestones — foundation, framing, rough MEP, and a final inspection — each verifying the work matches the approved drawings before the next phase can proceed. The CO is typically issued only after the final inspection confirms everything was built as permitted.

New construction and any change of occupancy classification (converting a house to a duplex, or retail space to a restaurant, for example) almost always require a new CO. Many jurisdictions also require one for additions and significant renovations, even when the building's use isn't changing — it's worth confirming this alongside your permit application rather than assuming it only applies to brand-new buildings.

Occupying a building without a required CO carries similar risk to building without a permit in the first place — it can block a sale or lease, complicate insurance and financing, and in some jurisdictions result in fines for occupying an uninspected structure. Because it's the final step rather than the first, it's also the one most likely to get overlooked once the visible construction work is done.