After bonds are issued under this subchapter, the governing body of the municipality shall establish the rates, tolls, and charges for service provided by the municipality's waterworks system, or combined waterworks and sanitary sewer system if appropriate, in amounts sufficient to:
(1) pay the cost of operating and maintaining the system;
(2) pay when due the principal of and interest on the bonds; and
(3) establish and maintain the reserve fund and other funds prescribed by the ordinance authorizing the bonds.