Discharge of Sewage and Waste
If you have a vessel with installed toilet facilities, it must have an operable marine sanitation device (MSD) on board and be designed to prevent discharge into the water.
There are three types of MSDs.
- Types I and II MSDs treat waste with special chemicals to kill bacteria. When in waters where treated sewage cannot be dumped overboard (for example, any freshwater body of water), these MSDs must have the Y valve secured so that it cannot be opened. This can be done by placing a lock or non-reusable seal on the Y valve or by taking the handle off the Y valve in a closed position.
- Type III MSDs provide no treatment and are either holding tanks or portable toilets. Collected waste should be taken ashore and disposed of in a pump-out or dump station or in an onshore toilet.
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.
Discharging treated sewage into coastal waters is permitted but discouraged. Avoid flushing your vessel's toilet in small bays, in marinas, and near shellfish beds.
Untreated sewage (even if it has been dosed with a deodorant product) CANNOT be discharged into inland or coastal waters.
The Washington Department of Ecology recently established Puget Sound and certain adjoining waters as a Vessel Sewage No Discharge Zone (NDZ). The NDZ is an area of water where discharging treated or untreated sewage from boats is prohibited.
All vessels operating in that area must retain sewage in a holding tank and discharge it properly on shore. The NDZ will help protect Washington’s public health, water quality, and sensitive resources.