Boat sewage laws and regulations

Federal and state laws and programs

Help keep Washington waters clean: learn the laws and regulations about the different types of sanitation devices.

Puget Sound is now a no-discharge zone for vessel sewage

The Washington State Department of Ecology has established a No Discharge Zone (NDZ) for Puget Sound and certain adjoining waters. An NDZ is a body of water where boats may not release sewage, whether treated or not. The NDZ will help protect public health, water quality, and sensitive resources.

Chapter 173-228 WAC was adopted on April 9, 2018 after a five year public process and EPA approval. The rule has been effective since May 10, 2018. However, certain commercial vessels have a five-year delay before the rule begins. There is no change for graywater discharges. For more information see the Department of Ecology’s No Discharge Zone Page.

Become a Pump Out, Don’t Dump Out campaign partner and help spread the message or get educational resources here (scroll down).

Map of the No Discharge Zone

The No Discharge Zone includes all Washington marine waters east of New Dungeness Light, at the east end of the Strait of Juan de Fuca, plus Lake Washington, Lake Union, and the waters that connect them to Puget Sound.


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)

Discharge from a Type I or Type II MSD is illegal. You will need to secure your MSD in a manner which prevents discharge of treated or untreated sewage. See the Coast Guard regulations for more details.  Acceptable methods of securing the device include:

  • Closing the seacock and removing the handle;
  • Padlocking the seacock in the closed position;
  • Using a non-releasable wire-tie to hold the seacock in the closed position; or
  • Locking the door to the space enclosing the toilets with a padlock or door handle key lock.

Related boating laws, regulations and programs

Types of marine sanitation devices (MSDs): Types of Coast Guard-certified MSDs

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