The board shall review not less often than every two (2) years the contribution of users and user classes, the total cost of operation and maintenance of the treatment works and its approved user charge system. The board shall revise the charges for users or user classes to accomplish the following:
A. Maintain the proportionate distribution of operation and maintenance costs among users and user classes as required herein.
B. Generate sufficient revenue to pay the total operation and maintenance costs necessary for the proper operation and maintenance (including necessary equipment replacement) of the treatment works.
C. Apply excess revenues collected from a class of users to the costs of operation and maintenance for the next year and adjust the rate accordingly. (Ord. 453, 11-29-1990)