NYC Affordability

The Certificate of Occupancy is the NYC Department of Buildings’ record of what a building is legally allowed to be used for and how many units it’s allowed to contain: residential, commercial, mixed-use, manufacturing, and so on. A building generally can’t be legally occupied without a valid C of O (or, for older buildings, an equivalent occupancy record) that actually matches its real-world use.

This matters most for converted buildings: a pre-war factory turned into residential lofts, or a building where a unit count was informally added without amending the paperwork, can end up with a C of O that doesn’t match reality. That mismatch typically surfaces during a title search, and it isn’t cosmetic. It can complicate financing, insurance, and resale until it’s fixed with an architect and a DOB filing. Some buildings also operate for years under a Temporary Certificate of Occupancy (TCO) rather than a final one, which is worth specifically asking about before buying.

Worked example

A buyer under contract on a loft in a converted manufacturing building discovers during attorney review that the C of O still lists “manufacturing” use, not residential. Resolving it can take months and require an architect and DOB expeditor, exactly the kind of issue an attorney review period exists to catch. See NYC closing costs for buyers for where attorney review fits in the purchase timeline.