Marine Sanitation Devices

by Mark Deschane


We have all heard horror stories about boaters being fined large sums of money for overboard discharge of sewage in a no discharge zone. We should all understand that this is absolutely not allowed. There is no location that inland boaters can get to where this option would be allowed. Being a marine surveyor, it is quite apparent to me that a few of us do not understand what needs to be done to make our MSD installations legal.

Do you?

In the interest of finding out if large fines had ever been levied against a boater, I made a phone call to Boat/US and was told the Maximum fine recorded was $2,000.00 for dumping sewage in a no discharge zone. I then asked if Boat/US had any records of fines levied for an MSD which was not in compliance with Federal Law. The person said that Boat/US did not have any records of this type on file.

So, what is a legal MSD and should I be concerned? Let's look at how easy it is to correct this problem, if it exists, and I think you'll agree that it makes sense to be concerned. Also, because I could not substantiate any fines, doesn't mean they haven't, or will not occur!

First of all there are three types of Marine Sanitation Devices; Type I, II and III. Type I and II are really sewage treatment devices. A "TYPE I marine sanitation device" means a device that, under the test conditions described by law, produces an effluent having a fecal coliform bacteria count not greater than 1,000 per 100 milliliters and no visible floating solids. "TYPE II marine sanitation device" means a device that, under the test conditions described by law, produces an effluent having a fecal coliform bacteria count not greater than 200 per 100 milliliters and suspended solids not greater than 150 milligrams per liter. "TYPE III marine sanitation device" means a device that is designed to prevent the overboard discharge of treated or untreated sewage or any waste derived from sewage (This is a holding tank).

TYPE I and II MSDs are allowed on the Mississippi River, below Lock and Dam number 2 and on the Great Lakes! However, these systems are expensive, and not normally found on recreational vessels and are therefore not the focus of this article.

TYPE III MSDs are common and would include the Porta-Potti and the marine head connected to a holding tank. The problem with TYPE III MSDs is there are many adaptations which allow overboard discharge and it is the adaptations which may not be legal.

Lets look at a TYPE III MSD in it's absolute simplest form, a head with a water supply line and a waste hose connected to the top of a holding tank with another hose from the bottom of the holding tank connected to a pump-out connection, usually at the deck. The system must also be vented. As just described, this system is legal everywhere.

There are variations of TYPE III MSD systems: A Y-valve located in the hose from the head to the holding tank with the third connection of the Y-valve connected to a hose leading to an overboard discharge seacock. Another variation would be to have the Y-valve located in the holding tank pump-out hose, again with the third connection of the Y-valve having a hose connected to the overboard discharge seacock. This second system needs to have a pump in the overboard discharge hose to pump the contents of the holding tank overboard. This pump also acts as a check valve when the seacock has been opened for overboard discharge. Without this pump, you would not be able to discharge the holding tank and seawater (lake water) would fill your holding tank. (Very good schematics of these systems are shown in the 1997 West Marine Catalog, page 463). Of the two variations described, the second allows the most flexibility; use of the holding tank when in a No Discharge Zone and the ability to pump the holding tank overboard when outside the No Discharge Zone.

However, as described, these systems are illegal, unless beyond the legal limit, or the Y- valve or seacock has been secured in the closed position while operating upon waters which are No Discharge Zones.

So, the question is; How are the valves secured in the closed position? Get access to a FAX machine and write down this telephone number 1-(703)-313-5931. This is the phone number for the United States Coast Guard's FAX-ON-DEMAND service. When you are asked for the document you would like to receive, punch in document 612. Better yet, ask to receive the document entitled INDEX OF DOCUMENTS, this document gives you the code number for 68 different documents or FACT SHEETS available from the US Coast Guard's FAX ON DEMAND service.

The following two paragraphs are excerpted from USCG Document 612:


It is illegal to discharge raw sewage from a vessel in territorial waters (within the 3 mile limit), the Great lakes, and navigable rivers. However, a valve may be installed on any MSD to provide for the direct discharge of raw sewage when the vessel is outside U.S. territorial waters. The valve must be secured in a closed position while operating in U.S. waters. As described under NO DISCHARGE ZONES, use of a padlock, non-releasable wire-tie, or the removal of the valve handle would be considered adequate securing of the device. The method chosen must be one that presents a physical barrier to the use of the valve.

NOTE: The boundaries of U.S. territorial waters are marked on some nautical charts. Changes to the boundaries are published in Coast Guard Local Notices to Mariners.

I have received word from Kim Elverum of the Boat and Water Safety Section, Minnesota DNR and William Engfer, Boating Law Administrator, Wisconsin DNR that the statements above by the United States Coast Guard on securing the overboard discharge capabilities of TYPE III MSDs is legal in these states. Contact your Boating Law Administrator if you are from a different state then mentioned.

I have been informed that Canada does not accept this method of securing the overboard discharge capabilities of your MSD system. It is my understanding that in Canadian waters you must only have a holding tank and no hoses are to be connected to overboard discharge seacocks. This is important information for you sailors sailing to Canadian waters during your cruising season. Don't get caught!

Finally, if your boat is set-up such as described above, understand that seacocks and Y-valves are mechanical devices and as such, they need occasional exercise. At least once a year (preferably twice) open and close or work these valves so they remain in good working order. If they quit working, disassembly and lubrication (if possible) is in order.

Given the simplicity of securing the valves outlined above, there is no reason to have not taken care of this problem. •

Mark Deschane is a marine surveyor located near Walker, MN.