Water Quality photo identifier

Water Quality Program


  • Always use sewage pumpouts, Porta-potti dump stations or mobile pumpout services. Washington State Parks Pumpout Station Information
  • Do not discharge treated or untreated sewage in the water. However if you must discharge, current regulations only allow for discharges from Type I or Type II Marine Sanitation Devices (described below). Ecology strongly advises that discharges from Type I and Type II devices occur while the vessel is underway and that boaters avoid discharges while in port. Marina operators may have rules that prohibit discharge from Type I and Type II devices as a condition of a moorage lease. It is illegal to discharge at any time from Type III Marine Sanitation Devices.
  • Discharge of untreated sewage is illegal in Puget Sound, and in the Strait of Juan de Fuca. It is only allowed if you are three or more nautical miles off Washington’s outer Pacific coast.
  • Boats with an onboard toilet are required to have a U.S. Coast Guard certified marine sanitation device (MSD), preferably a Type III holding tank. (See chart below.)
  • Bring portable toilets ashore for proper waste disposal.
  • Use onshore restroom facilities when at dock.

To report sewage spills and other pollution, call the U.S. Coast Guard at 800-424-8802 and Washington Emergency Management Division at 800-OILS-911.

Types of Marine Sanitation Devices (MSDs) and Treatment Systems

Type I

Type II

Type III

Treats sewage before discharge by chopping or macerating. May add disinfectant chemicals. Disintegrates solids before discharging into water.

Discharge must meet certain health standards for bacteria content; must not show any visible floating solids.

Only allowed on vessels smaller than 65 feet in length.

Being phased out of use on larger vessels. Only allowed if equipment was on vessel before Jan. 1978.

Provides higher level of treatment than Type I. Treats sewage by biological means before discharging. Separates solids for incineration or pumpout.

Effluent is cleaner than Type I, but contains greater level of chemicals.

Usually requires more space and power than Type I.

Usually installed on larger vessels only.

Does not allow the discharge of sewage. Includes re-circulating, incinerating MSDs and holding tanks.

Holding tanks are the most common kind of Type III MSD used on recreational boats. Waste is stored until it can be pumped out to a reception facility.

Holding tank waste is not treated even if odor-reducing chemicals are added.

Allows for “Y-valve” to discharge directly overboard while outside the three nautical mile limit along Washington's outer coast.

All inland waters of Washington State which includes the Strait of Juan de Fuca and Puget Sound are considered Washington State waters. Discharges into these waters from Type III devices are prohibited.

Report all spills to 800-OILS-911 and 800-424-8802