Michigan Compiled Laws, Chapter 121. Charter Water Authority § 121.25

Sec. 25. The authority and any municipality which is not a part thereof, may enter into a contract for the furnishing of water service from any water supply and transmission system owned or operated by the authority. The contract shall provide for reasonable charges or rates for the service furnished, which shall be not less than the rates charged to municipalities of the same classification which are a part of the authority. Any income derived from such contracts shall be applied and used by the authority in the same manner as provided in section 9 of this act.  1 No such contract shall be for a period exceeding 40 years.