(A)   The wastewater service charge for the use of and for service supplied by the wastewater facilities of the city shall consist of a basic user charge for operation and maintenance plus replacement, a debt service charge and a surcharge, if applicable.
   (B)   The monthly debt service charge shall be computed by dividing the annual debt service of all outstanding bonds by 12 and further dividing by the number of gallons billed for that month arriving at a charge per gallon billed.
   (C)   The basic user charge shall be based on water usage as recorded by water meters and/or sewage meters for wastes having the following normal concentrations:
      (1)   A five-day 20°C BOD of 240 mg/l; and
      (2)   A SS content of 240 mg/l.
   (D)   It shall consist of operation and maintenance costs, plus replacement and shall be computed as follows:
      (1)   Estimate the projected annual revenue required to operate and maintain the wastewater facilities including a replacement fund for the year, for all works categories;
      (2)   Proportion the estimated costs to the wastewater facility categories by 40% of cost attributed to volume, 30% attributed to suspended solids and 30% attributed to BOD;
      (3)   Estimate wastewater volume, pounds of SS and pounds of BOD to be treated;
      (4)   Proportion the estimated costs to non-industrial and industrial users by volume, suspended solids and BOD;
      (5)   Compute costs per 1,000 gallons for normal sewage strength; and
      (6)   Compute surcharge costs per 1,000 gallons per mg/l in excess of normal sewage strength for BOD and SS.
   (E)   A surcharge will be levied to all users whose waters exceed the normal concentrations for BOD (240 mg/l) and SS (240 mg/l). The surcharge will be based on water usage as recorded by water meters and/or sewage meters for all wastes which exceed the 240 mg/l and 240 mg/l concentration for BOD and SS respectively. Division (F) below specifies the procedure to compute a surcharge.
   (F)   The adequacy of the wastewater service charge shall be reviewed annually by certified public accountants for the city in their annual audit report. The wastewater service charge shall be revised periodically to reflect a change in debt service or a change in operation and maintenance costs, including replacement costs.
(Ord. 5, Series 1981-1982, passed 8-24-1981)