(a) A water authority formed pursuant to this chapter shall be operated without profit, but the rates, fees, rents, or other charges for water or wastewater collection, disposal, and treatment and other facilities, supplies, equipment, or services furnished by the water authority shall be sufficient at all times:
(1) To pay all operating and maintenance expenses necessary or desirable for the prudent conduct of its affairs and the principal of and interest on the obligations issued or assumed by the water authority in the performance of the purposes for which it was organized; and
(2) For the creation of adequate reserves.
(b) The revenues of the water authority shall be devoted first to the payment of operating and maintenance expenses and the principal and interest on outstanding obligations, and thereafter to reserves for improvements, new construction, depreciation, and contingencies as the board of directors may prescribe from time to time and to other purposes approved by the board, including rebates to water users.