Under New Hampshire law, it is illegal to discharge sewage and graywater (shower and sink waste) from a boat to any fresh water. Under federal law, it is illegal to discharge raw sewage from a boat within three miles of the coast (tidal waters). However, some coastal areas in the United States are considered "No Discharge Areas" where no boat sewage, whether treated or untreated, may be discharged. New Hampshire's coastal waters were recently designated a No Discharge Area.

If your boat has an installed toilet, it must be a U.S. Coast Guard certified marine sanitation device (MSD). Type I or II MSDs treat sewage and discharge it into the water. Type III MSDs include holding tanks that retain untreated sewage to be discharged at an onshore pumpout facility or through a Y-valve once boaters have exceeded the three mile limit. Portable toilets are not regulated as MSDs, however the provisions apply to these as well. Thus for fresh waters, only holding tanks without Y-valves and portable toilets are allowed.

This table was adapted from the EPA Office of Water website: www.epa.gov/owow/oceans/vessel_sewage/vsdmsd.html.

The sewage disposal system you select will depend on your boat's design, space configuration, and electrical system. Other things to consider when selecting a sewage disposal system are the cost to retrofit your boat and if you boat in a No Discharge Area. Boaters can choose a treatment device, a holding tank, or a combination of the two, depending on where the boat is to be used. Holding tank capacity depends on the number of people customarily aboard, usual trip length, and whether you anchor or use marinas offering toilet and/or pumpout facilities. Other options include manual, electrical, or vacuum toilets; pipes or hoses; and flexible or rigid tanks. Many owners of smaller craft can opt for less costly portable toilets.

Articles in recent boating periodicals or boating websites are a great resource for detailed information on properly equipping your boat. Some things to consider include:

• If you use hose, buy "waste quality" hose to reduce odors and leaks.
• Use gradual curves rather than elbows at connections to avoid clogging, and make hose runs and vent lines as short as possible.
• Install vent fittings above the holding tank and above the waterline. Vent lines should have a constant rise from holding tank top to vent and include a gooseneck above the vent to avoid water back flooding.

For More Information

For more information go to www.des.nh.gov/wmb/cva/ or contact the Clean Vessel Act Program, NH Department of Environmental Services, PO Box 95, Concord, NH 03302-0095; (603) 271-3414.