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If you have a recreational vessel with installed toilet facilities, it must have an operable marine sanitation device (MSD) on board.

There are three types of MSDs.

  • Types I and II MSDs are usually found on large vessels. Waste is treated with special chemicals to kill bacteria before the waste is discharged.
  • Type III MSDs, the simplest and most common, consist of holding tanks or portable toilets. They require only a small storage space and are simple to operate. Type III MSDs have the least effect on the environment since the waste is to be discharged on shore into a local sewage treatment facility such as a pump-out station.
Pump-Out Station
Marine Sanitation Device diagram

While a vessel with an installed toilet is on Maryland or federally controlled waters, the operator must ensure that there is no possibility of discharging sewage overboard.

  • Types I and II MSDs with “Y” valves must be secured by bypassing, locking, securing, or disabling the valve by using a padlock or non-reusable seal or by removing the valve handle so that waste cannot be directed overboard.
  • Vessels with a Type III MSD must disconnect or physically block any on-board sewage lines or hull fittings that would allow waste to be discharged overboard.

Vessels 65 feet or less in length may use a Type I, II, or III MSD. Vessels more than 65 feet in length must install a Type II or III MSD.

All installed devices must be U.S. Coast Guard-certified.

Pump-Out Station Sign

Pump-Out Station sign
Signs like these are posted at pump-out stations in Maryland.

For more information on pump-out stations, visit the Maryland Department of Natural Resources Boating Services website or call 410-260-8772.