(a) The board shall impose rates and other charges for the sale or use of water, water connections, power, electric energy, or other services the authority sells, provides, or supplies.
(b) The rates and other charges must be reasonable, nondiscriminatory, and sufficient to provide revenue adequate to:
(1) pay all expenses necessary to the operation, maintenance, and replacement of and the making of additions to the authority's properties and facilities;
(2) pay the principal of, the interest on, and any premium on all bonds issued under this chapter when they become due and payable;
(3) pay all sinking fund or reserve fund payments agreed to be made with respect to any of those bonds and payable out of that revenue when and as they become due and payable;
(4) fulfill the terms of any agreements made with the holders of those bonds or with any person in their behalf; and
(5) discharge all other lawful obligations of the authority when they become due.
(c) The rates and other charges may not exceed the amount that may be necessary to fulfill the obligations imposed on the authority by this chapter.