Rates, fees, charges, rentals, and licenses for services rendered by the district or facilities provided by the district from any of its projects shall be so fixed and, from time to time, revised as at all times to provide funds at least sufficient, taking into account other sources for the payment thereof, to:
(1) Pay the cost of operating, maintaining, repairing, replacing, extending, and improving the project or projects of the district.
(2) Pay the principal of and the interest on all bonds issued and obligations assumed by the district that are payable out of the revenues derived from operation of the project or projects of the district as the said principal and interest become due and payable.
(3) Create and maintain such reserves for the foregoing purposes or any of them as may be provided in any trust indenture executed by the district under this chapter or in any resolutions of the board authorizing the issuance of bonds, the assumption of any obligation, or the acquisition of any such project.
(4) Make such annual payments, if any, to the United States of America or any agency or instrumentality thereof, the state, municipalities, counties, departments, authorities, agencies, and political subdivisions of the state and any public corporations organized under the laws of the state as the district may have contracted to make.