Each licensee shall annually file a verified inventory record indicating purchases and sale of fuel, to indicate whether or not there is any abnormal or unexplained loss of fuel in any underground storage tank on the premises of such licensee; that in event such records indicate any abnormal or unexplained loss of fuel, the fire chief may then require a pressure testing of said underground storage tanks upon giving five (5) days' notice by certified mail to the owner and/or licensee of said premises. (1972 Code)