Effective May 10, 2018 a No Discharge Zone (NDZ) is being established for Puget Sound and certain surrounding waters. The No Discharge Zone includes all Washington marine waters east of New Dungeness Lighthouse, 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.
What is the No Discharge Zone?
A designated NDZ is a body of water where all sewage, whether treated or not, is prohibited from being discharged from vessels. The purpose of the NDZ is to protect public health, water quality and sensitive resources. There is no change for greywater discharges.
Some commercial vessels have a five-year delay before the rule applies, see Chapter 173-228 WAC  for details.
Where can I dispose of boat sewage?
You can use stationary pumpouts, mobile pumpouts boats, or discharge outside the NDZ following state requirements.