It shall be unlawful for any person, firm or corporation to make connection to a supply of gas or water for which an inspection is required, or which has been disconnected by the order of the Plumbing Inspector, until a certificate of approval has been issued by the Plumbing Inspector authorizing the connection and use of such plumbing or plumbing system. The Plumbing Inspector may, at his or her discretion, authorize a temporary connection.