The governing authorities of any municipality shall devote all monies of the system derived from any source other than the issuance of bonds for purposes authorized by the laws of the State of Mississippi, to or for the payment of all operating expenses, including such items as are normally required of utilities for sales development; to or for the payment of all bonds and interest on outstanding revenue bonds, if any, of such system; to or for the acquisition and improvement of the system contingencies; to or for the payment of all other obligations incurred in the operation and maintenance of the system and the furnishing of service; and to or for the creation and maintenance of a cash working fund or a surplus fund to be used for replacement, extension of systems and emergencies. The balance of any monies, including but not limited to, any which have heretofore been classified as revenues or surplus of such system, if any, may be used for any lawful, municipal purpose and may be paid to the governing authorities of the municipality for distribution to the various municipal funds or may be disbursed for such purpose by the governing authorities at their direction. The purpose of any allocation or expenditure of money made pursuant to this section shall be spread upon the minutes of the municipal governing authorities.