Mich. Comp. Laws § 123.355

Sec. 5. A city so acquiring such a system may readjust the service rates provided the same do not impair the obligation of any bond contract. The legislative body of a city may, subject to constitutional and statutory limitations, adopt such ordinances and resolutions as may be necessary for the care, protection, preservation, management and control of any system acquired pursuant to this act, including that portion outside its city limits.