Type III marine sanitation devices (boat toilets with holding tanks) composting toilets and portable toilets
Discharge of untreated sewage is illegal in all inland Washington waters, including Puget Sound and the Strait of Juan de Fuca. It is only allowed if you are three or more nautical miles off the outer Pacific coast.
Type I and Type II marine sanitation devices (MSDs)
Although permitted by law, discharge from Types I and II MSDs is not recommended, especially near swimming beaches and shellfish-growing areas. Even treated sewage can contain high levels of bacteria and chemicals, and it adds oxygen-robbing nutrients to the water. Some marinas prohibit discharge from Type I and II MSDs.
Related boating laws, regulations and programs
Types of marine sanitation devices (MSDs): Types of Coast Guard-certified MSDs
Washington State boat sewage regulations: Types of MSDs and sewage disposal guidelines and regulations
Washington boater education course — waste, oil and trash disposal: Washington and federal requirements for disposing of sewage, trash, oil and other hazardous substances from vessels
Washington State Parks Boating Program: How to get a boater education card, register your boat, find moorage, and more
Clean Vessel Act: Overview of the federal CVA, which provides grants to states to build and maintain pumpout stations for recreational boaters
Clean Boating Act: The federal CBA regulates discharges other than sewage from recreational vessels