It shall be the mandatory duty of any reorganized common sewer district issuing any general or special revenue bonds under sections 204.600 to 204.640 to:

(1) Fix and maintain rates and make and collect charges for the use and services of the system, for the benefit of which revenue bonds were issued, sufficient to pay the cost of maintenance and operation;

(2) Pay the principal of and the interest on all revenue bonds issued by the reorganized common sewer district chargeable to the revenues of the system; and

(3) Provide funds ample to meet all valid and reasonable requirements of the resolution by which the revenue bonds have been issued.

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From time to time, the rates shall be revised to meet fully the requirements of sections 204.600 to 204.640. As long as any bond issued or the interest thereon shall remain outstanding and unpaid, rates and charges sufficient to meet the requirements of this section shall be maintained and collected by the reorganized common sewer district that issued the bonds.