In the event of a meter being out of order and failing to register properly, the consumer shall be back charged or refunded the difference between the billing volume they were charged for and the average volume of monthly consumption as shown by the meter when the meter was in proper working order as determined by the city. The maximum period of billing adjustment is three years. (Ord. 5849 § 1, 2004; Ord. 5216 § 1, 1999; Ord. 4878 § 3, 1996.)