(a) The board shall set and revise the rates of compensation for:
(1) water the authority sells; and
(2) services the authority renders.
(b) The rates of compensation must be sufficient to:
(1) pay the expense of operating and maintaining the authority's facilities;
(2) pay the bonds as they mature and the interest as it accrues; and
(3) maintain the reserve and other funds as provided in the resolution authorizing the bonds.