The cost to be recovered pursuant to this chapter and the unit cost to be fixed by the Council shall be determined and allocated in each of the following categories:
(A) "Category A" - Debt Service for Water Facilities. The amount of the annual interest and principal cost necessary to retire the bond issued to pay for the local share of the project cost. The amounts collected to retire this bond issue will be designated in a separate account, "Debt Services Costs".
(B) "Category B" - Operation and Maintenance - City Water System. The annual cost of operating and maintaining the city water system facilities, including an amount for replacement costs, which shall be segregated in a separate fund designated "Operation and Maintenance Costs" and "Replacement Costs" respectively.