Mich. Comp. Laws § 121.24

Sec. 24. The legislative body of each municipality which is a part of the authority may advance or loan to the authority any moneys required for administrative expenses or for the purpose of obtaining maps, plans, designs, specifications and cost estimates of a proposed water supply and transmission system. Any advances or loans may be included as a part of any bond issue by the authority under the provisions of this act, and repaid to the municipality upon the sale of the bonds.