Mich. Comp. Laws § 324.9506
All watercraft moored, operated, or located upon the waters of this state are subject to inspection by the department, or any peace, conservation, or police officer for the purpose of determining if the watercraft is equipped in compliance with the requirements of this part. The department may inspect marinas and other waterside facilities used by watercraft for launching, docking, or mooring purposes to determine if they are equipped with trash receptacles, sewage disposal equipment, or both. Commercial docks and wharfs designed for receiving and loading cargo or freight, or both, from commercial watercraft shall furnish facilities, if determined necessary, as prescribed by the department, to accommodate discharge of sewage from heads and galleys and for deposit of litter, garbage, trash, or bilge waters from the watercraft that utilize the docks or wharfs.
MCL 324.9506