The rates hereby fixed are estimated to be sufficient to provide for the payment of the expenses of administration and operation, such expenses for maintenance of the system as are necessary to preserve the same in good repair and working order, to provide for the payment of the principal of and interest on all general obligation bonds of the city, issued for water or sewer purposes, as the same becomes due, and to provide for such other expenditures and funds for the system as this subchapter may require. Such rates shall be fixed and revised from time to time as may be necessary to produce these amounts.
(Ord. 78, passed - - )