A certificate of occupancy (CO, also called C of O) is a document issued by a local government agency or building department certifying a building's compliance with applicable building codes and other laws, and indicating it to be in a condition suitable for occupancy.

The procedure and requirements for the certificate vary widely from jurisdiction to jurisdiction and on the type of structure. In the United States, obtaining a certificate is generally required whenever:

  • a new building is constructed
  • a building built for one use is to be used for another (e.g., an industrial building converted for residential use)
  • occupancy of a commercial or industrial building changes, or ownership of a commercial, industrial, or multiple-family residential building changes

A certificate of occupancy is evidence that the building complies substantially with the plans and specifications that have been submitted to, and approved by, the local authority. It complements a building permit—a document that must be filed by the applicant with the local authority before construction to indicate that the proposed construction will adhere to ordinances, codes, and laws.

Source: Wikipedia