Section 250.150 - Revenues to be kept separate - order of payments - records - transfers1. Whenever any such city, town or village or sewer district shall establish and collect rates and charges for the services of any sewerage system or any combined waterworks and sewerage system it shall be the mandatory duty of such city, town or village, or sewer district and of the proper officials thereof:(1) To segregate the revenues derived from the operation of such system from all other revenues or funds of such city, town or village or sewer district; to hold such funds separate and distinct from all other funds thereof and, if such funds shall be deposited in any bank, to maintain such deposits as an account separate and distinct from all other bank accounts thereof.(2) Such revenues shall be devoted, first, to the payment of the expenses of operating and maintaining such system; second, to the payment of any and all bonds or other obligations payable from such revenues; third, to the establishment of a proper depreciation reserve for the benefit of such system; fourth, to the fulfillment of any covenants or agreements contained in any ordinance which may have authorized outstanding revenue bonds issued for the benefit of such system and, fifth, for the payment of the cost of improvements and extensions to such system.(3) To install and maintain proper books of records and accounts (entirely separate from all other records and accounts of the city, town or village or sewer district) in which correct entries shall be made of all dealings or transactions of or in relation to the properties, business and affairs of the sewerage system or of the combined waterworks and sewerage system. Such accounts shall show the amount of revenues received from the system, the application of such revenues and all financial transactions in connection therewith. At least once a year such accounts shall be audited properly by a public accountant employed for that purpose to be paid from the revenues received from the system. Such audits shall at all times, during usual business hours, be open to the examination and inspection by any taxpayer, any user of the services of the system or any holder of any bonds issued pursuant to this chapter or by anyone acting for or on behalf of any such taxpayer, user or bondholder. Such books of records and accounts and such audits shall conform to any reasonable and valid covenant or agreement with respect thereto set out in any ordinance which may authorize the issuance of bonds pursuant to this chapter.(4) To perform all duties with respect to the operation of any such sewerage system or combined waterworks and sewerage system or with respect to the revenues derived or to be derived from the operation thereof imposed by law or set out in any reasonable and valid covenant and agreement contained in any ordinance which shall authorize the issuance of revenue bonds under this chapter.2. No transfer of any funds derived from the operation of any sewerage system or combined waterworks and sewerage system to any other funds of the city, town or village or sewer district shall be made except by action of the governing body thereof and no such transfer shall be made unless all expenses of operation and maintenance of said system shall have been paid, unless the principal of and the interest on all bonds due at the time of said transfer shall have been paid, and unless all covenants and agreements requiring the payment of money, set out in the ordinance authorizing any outstanding revenue bonds shall have been met and unless all obligations requiring the payment of money payable from such revenues then due shall have been met. No payments of any indebtedness or expenses incurred by any such city, town or village or sewer district other than those above stated in subdivision (2) shall be made from the revenues derived from the operation of any such system unless such revenues shall have been transferred to other funds of the city, town or village or sewer district under the conditions prescribed by this subsection.