If revenue bonds are issued in accordance with the provisions of chapter 9-40, the sanitary district shall, until all such bonds and interest on the bonds are fully paid, fix such rates and charges and revise them from time to time in such manner that the collections of the charges will be adequate to:

1. (1) Pay all current, reasonable, and necessary expenses of the operation and maintenance of all facilities whose revenues are pledged for the payment of the bonds;
2. (2) Produce net revenues, in excess of such current costs of operation and maintenance, at all times sufficient to pay the principal and interest due on the bonds; and
3. (3) Accumulate and maintain reserves for the further security of the bonds in such amounts as are agreed in the resolutions authorizing the bonds.

Source: SDC Supp 1960, § 45.3815 (8) as added by SL 1964, ch 144 , § 7; SDCL § 34-17-30; SL 2011, ch 165 , § 97.