Mich. Comp. Laws § 124.113

Sec. 3. (1) Two or more local governments or 1 or more local governments and a public agency are authorized to enter into a contract with each other to form a joint endeavor to perform or exercise any function, service, power, or privilege that the local government or public agency could each exercise separately. (2) A contract entered into pursuant to subsection (1) shall be approved by resolution of the governing body of each participating local government.