Miss. Code § 21-27-47
Any municipality having outstanding bonds issued pursuant to the authority granted in Section 21-27-23 shall maintain rates for all the services and facilities afforded by any system, the revenues of which are pledged to the payment of such bonds, which rates shall be sufficient at all times to maintain an interest and bond redemption fund sufficient to pay the interest on and principal of such bonds as and when the same become due and payable and, if so provided in the ordinance authorizing such bonds, to accumulate a reserve in such fund, and to provide for the payment of such cost of operation and maintenance as may be necessary to keep such system at all times in good repair and working order. Such rates shall be fixed by separate ordinance precedent to or at the time of the issuance of such bonds and shall be revised from time to time so as to produce the amounts necessary to provide for the foregoing. Bonds issued pursuant to the authority granted in Section 21-27-23 to acquire or improve a system shall be secured by a pledge of an amount of the gross revenues of such system sufficient to maintain such an interest and bond redemption fund. However, if there are then outstanding bonds to the payment of which the revenues of a system have been previously pledged, then, until said outstanding bonds have been retired, bonds issued to improve such system shall be secured by a pledge of the revenues of the system in such an amount only after deductions have been made for servicing the said outstanding bonds and for maintaining and operating the system. Notwithstanding the above provisions, all revenue bonds issued for a specific utility may be issued on an equivalent basis, provided that each and every ordinance authorizing each and every bond issued shall clearly state the basis on which future revenue bond issues shall be provided for in order to place them on an equivalent basis with prior issues.
Miss. Code § 21-27-47