Mich. Comp. Laws § 124.259

Sec. 9. For the purpose of acquiring, improving, enlarging and/or extending a water supply system, the authority may issue self-liquidating revenue bonds in accordance with the provisions of Act No. 94 of the Public Acts of 1933, being sections 141.101 to 141.139, inclusive, of the Compiled Laws of 1948, as now or hereafter amended, or any other act providing for the issuance of such bonds: Provided, That no such bonds shall be a general obligation of the authority, but shall be payable solely from the revenues of the water supply system.