(A) The city, or its city engineer, shall determine each user's average daily volume of wastewater, which has been discharged to the wastewater system, which shall then be divided by the average daily volume of all wastewater discharged to the wastewater system, to determine each user's volume contribution percentage. The amount used is the total average contribution percentage. The amount used as the total average daily volume of wastewater shall exclude infiltration and inflow. The city, or its city engineer, shall determine each user's average daily poundage of 5-day, 20° Centigrade biochemical oxygen demand which has been discharged to the wastewater system, which shall then be divided by the average daily poundage of all 5-day, 20° Centigrade biochemical oxygen demand discharged to the wastewater system to determine each user's biochemical oxygen demand contribution percentage.
(B) The city, or its city engineer, shall determine each user's average suspended solids poundage which has been discharged to the wastewater, to determine the user's suspended solids contribution percentage. Each user's volume contribution percentage, biochemical oxygen demand contribution percentage and suspended solids contribution percentage shall be multiplied by the annual operation and maintenance costs for wastewater treatment of the total volume flow, of the total 5-day, 20° Centigrade biochemical oxygen demand and of the total suspended solids, respectively.
(Prior Code, § 13.08.050)