Minn. Stat. § 86B.325: DISCHARGE FROM MARINE TOILETS PROHIBITED.

(a) A person owning or operating a watercraft or other marine conveyance on the waters of this state may not use, operate, or allow the use or operation of a marine toilet or similar device for the disposition of sewage or other wastes unless the toilet wastes are retained for disposition on land by means of facilities constructed and operated in accordance with rules adopted by the state commissioner of health and approved by the Pollution Control Agency.

(b) A person may not:

(1) discharge sewage or other wastes into the waters of this state directly or indirectly from a watercraft or other marine conveyance; or

(2) place, leave, discharge, or cause to be placed, left, or discharged a container of sewage or other wastes into waters of this state by a person whether or not the owner, operator, guest, or occupant of a watercraft or other marine conveyance.

(c) Toilets must be sealed or otherwise rendered inoperative so that human or other waste cannot be discharged from the toilet into waters of this state.