The Village shall annually review the wastewater contribution of sewer users and sewer user classes, the operation and maintenance expenses of the treatment facilities, and the sewer service charge system. The auditor may review the Village's billing practice on an annual basis.
The Village may revise the sewer service charge system to accomplish the following:
A. 
Maintain a proportionate distribution of operation and maintenance expenses among sewer users and sewer user classes;
B. 
Generate sufficient revenues to pay for the total operation and maintenance expenses (including replacement costs) of the wastewater treatment facility; and
C. 
Apply excess revenues collected from sewer users to the operation and maintenance expenses.