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A Boater's Guide to Sewage Holding Tank Systems for Recreational Boats

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Boat owners and repairers...

This online reference will help you install or upgrade sewage holding tank systems to be in compliance with existing laws governing marine sanitation devices (MSD's). You will find information on how to choose a system, sewage system design and the selection of system components, plus helpful tips for installation and maintenance.

What is the law?

In response to growing fears of the "death" of our nation's bodies of water, Congress enacted the Clean Water Act of 1972 (amended in 1987). This law addresses a wide spectrum of water pollution problems, including marine sewage from boats in navigable U.S. waters including coastal waters up to three miles offshore. The law further provides for "no discharge" by boats operated in enclosed lakes and reservoirs or in rivers not capable of interstate navigation. States may apply to the EPA to have certain other waters declared "no discharge zones" if discharge of treated sewage would be harmful. In short, boats with installed toilets must have an operable Coast Guard approved MSD designed to either hold sewage for pumpout ashore or for discharge in the ocean beyond the three mile limit, or to treat the sewage to Federal standards prior to discharge.

Why should you act now to comply with this law?

First of all, it is the law! All boats built since 1977 with installed toilets must have an operable approved type I, II or III MSD. Since 1980, all boats (including those built before 1977)with installed toilets must have an operable MSD.  Both the U.S. Coast Guard and the Natural Resources Police can enforce MSD requirements.

The arguments that boat sewage is "peanuts" compared to other sources of pollution, that holding tanks "stink," that there's no place to pump out, and that the law isn't being enforced anyway, is no longer valid. These facts are clear:

  • Growth in boating is placing an additional environmental strain on crowded recreational waters.
  • Government and citizens' groups are working aggressively to contain and prevent all forms of water pollution.
  • Government grant money is funding a tremendous increase in the number of pumpout facilities.
  • Advancing technology has provided a wide range of "user friendly" sanitation system options.

What are your choices for compliance?

There are three types of Coast Guard approved marine sanitation devices (MSDs):

  • Type I MSDs treat sewage so that the discharged effluent meets specified standards for bacteria content and contains no visible floating solids.
  • Type II MSDs are similar, but must meet a higher standard of sewage treatment.
  • Type III MSDs retain sewage for shore based disposal or discharge beyond the three mile offshore limit.

Boats 65 feet in length or less may install a type I, II, or III device. Vessels over 65 feet must install a type II or III MSD.

An approved treatment system (Type I or II) will have a label verifying that it meets the Coast Guard regulations for design and construction and the Environmental Protection Agency (EPA) regulations and standards as required by the Clean Water Act. Holding tanks (Type III) do not require a certification label if they simply store sewage at ambient temperatures and pressures.

What system should you install?

If the boat is operated in waters designated for "No Discharge", you only have one choice...you must retain all sewage, treated or not, for disposal ashore. Choosing the system that works best will depend on several factors. The answer to a few questions about how the boat is used should help you narrow the choices and determine optimal holding tank capacity:

  • How many people are usually on board for a trip?
  • Is the boat usually used for day trips or for longer periods and overnight cruises? Usually day trips do not generate much solid waste. Overnighting virtually guarantees it.
  • Does the boat anchor out overnight or tie up at a marina? When dockside, will you use the marina toilets?
  • Are pumpout facilities located nearby?
  • What are the boats design and space limitations for MSD installation?
  • Is the electric power supply adequate for an electrically operated system?

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