A user charge shall be levied on all users of the wastewater treatment works to provide funds necessary to pay for the cost of operation and maintenance of such works. The user charges must result in the distribution of all costs of operation and maintenance of the treatment works to each user, or user class, in proportion to such users contribution to the total wastewater loading of the treatment works. Factors such as strength, volume and delivery flow rate characteristics shall be considered and included as the basis for the user's contribution to ensure a proportional distribution of operation and maintenance costs. The method to be used to establish the user charges for wastes within the limits of normal concentrations (as defined in Section 929.02) shall be defined in this section. The method to be used to establish the user charge-extra strength surcharge for wastes in excess of normal concentrations shall be defined in Section 929.07.
The volume of wastewater from each user shall be subject to a user charge per 1,000 cubic feet, as follows:
(a) Charges for each billing period during acalendar year shall be based upon the following values for that calendar year:
(1) Estimated total operation and maintenance expenses, excluding those expenses attributable to debt service costs and excluding any expenses classified as reimbursable expenses;
(2) Estimated annual revenue from extra strength surcharges;
(3) Estimated total water consumption subject to sanitary sewer charges;
(4) Estimated administration and associated expenses for preparation and collection of billings.
(b) On the basis of the values in subsection (a) hereof, the base user charge per 1,000 cubic feet shall equal: [(1) plus (4) minus (2)] divided by (3), in 1,000 cubic feet.