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).

  • Discharge of untreated sewage is illegal within three nautical miles of shore.

  • 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.

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

NEW 7/21/2016 Read our petition to EPA to make Puget Sound a no-discharge zone for vessel sewage

Resource Manual for Pollution Prevention in Marinas

Hull Cleaning Advisory

Department of Ecology boater education news release

Washington State Parks Boater Education