The Handbook of Michigan Boating Laws and Responsibilities
The Official Boating Handbook of the Michigan Department of Natural Resources - Web Version
Table of Contents
Houseboats must have a wastewater holding system to prevent the discharge of waste into the water. Michigan law prohibits the discharge of any sewage, treated or untreated, into the fresh waters of Michigan.
If you have a recreational vessel with installed toilet facilities, it must have an operable marine sanitation device (MSD) on board. All installed devices must be U.S. Coast Guard–certified and working properly.
Types of MSDs
There are three types of MSDs.
Types I and II MSDs
Types I and II MSDs are usually found on large boats. Waste is treated with special chemicals to kill bacteria. The Y valve must be secured so that waste cannot be discharged into the water.
Type III MSDs
Type III MSDs, the simplest and most common, consist of holding tanks or portable toilets. Waste is to be taken ashore and disposed of in a pump-out facility station.