Mich. Comp. Laws § 123.151
Whenever 2 or more cities in Michigan determine to extend and improve their municipally owned water systems through the acquisition of an additional source of water supply consisting of a water supply line from one of the great lakes, bays thereof, and connecting waters between, together with related pumping station or stations, intake, meters, valves, rights of way, real estate and appurtenant apparatus and equipment (all of which are hereinafter referred to as the "source of supply"), such cities may jointly acquire, own and operate such source of supply, or any part thereof, and each such city may finance all or part of its agreed share of the cost thereof through the issuance of its water revenue bonds under the provisions of Act No. 94 of the Public Acts of 1933, as such act now exists or may hereafter be amended. The governing bodies of such cities are hereby empowered to enter into such agreements for the acquisition, operation, control, management and improvement of such source of supply (any which agreement may run for a term of years) as they may in their discretion see fit, including, but without limitation, agreements with each other, with water customers and with any board, agency or commission in which may be imposed the operation of the source of supply. Such agreements may provide for and fix the membership, powers and duties of a joint board, agency or commission to operate the source of supply, in which event the governing bodies may delegate to such board, agency or commission such of their powers with respect to the operation of the source of supply as they may see fit. Such board, agency or commission is empowered to enter into such agreements with said cities and with water consumers, including other cities, villages and public corporations, for the sale of water thereto and with respect to the operation of the source of supply, as may be consistent with the provisions of the agreements creating such board, agency or commission and as it may consider advantageous. The expense of the operation, maintenance, management, control and improvement of the source of supply may be paid either through the sale of water by the operating board to the cities and other customers, or by contributions to be made by the respective cities, or both, all as may be provided in the agreements between the cities, as originally entered into or as modified and supplemented from time to time.
MCL 123.151