Commercial vessels

It is now illegal for all commercial vessels to discharge treated or untreated sewage into Puget Sound. Chapter 173-228 WAC was adopted on April 9, 2018. The rule is effective as of May 10, 2018. There are a few exceptions and exemptions explained below or in our focus sheet

Puget Sound is a unique and sensitive environment that is prone to poor water quality conditions. A no discharge zone (NDZ) addresses this source of preventable pollution from impacting shellfish beds, beaches, and water quality.

Some vessels have until May 10, 2023 to comply

All vessels are still required to comply with existing state and federal discharge regulations in the interim. But because of costs and efforts to change systems, the vessels defined below have until 2023 to comply with the no discharge zone specific rules. All other vessels (not listed below) must comply with the rule starting May 10, 2018.

What is the boundary of the NDZ?

All the marine waters of Washington state inward from the line between New Dungeness Lighthouse (N 48°10'54.454", 123°06'37.004" W) and the Discovery Island Lighthouse (N 48°25'26.456", 123°13'29.554" W) to the Canadian border (intersecting at: N 48°20'05.782", 123°11'58.636" W), and fresh waters of Lake Washington, Lake Union, and connecting waters between and to Puget Sound.
Map of proposed no discharge zone. Includes all marine waters east of New Dungeness Lighthouse, plus lakes Union & Washington and waters connecting them to Puget Sound.

The NDZ is about 2,300 square miles in size. 

Public vessels emergency exemption 

There is an exemption for any public vessels that are actively involved in emergency, safety, security, or related contingency operations where it would not be possible to comply with the no discharge zone.

Public vessels means: a vessel owned or bareboat chartered and operated by the United States, by a state or political subdivision thereof, or by a foreign nation, except when such vessel is engaged in commerce.

How to manage vessel sewage in the NDZ

All Marine Sanitation Devices (MSDs) installed on all vessels shall be designed and operated to either retain, dispose of, or discharge sewage, shall be certified by the US Coast Guard, and follow requirements of 40 C.F.R part 140.

Type III holding tanks

Use stationary pumpouts, mobile pumpouts, pumping services (barges, trucks), or discharge outside the NDZ following requirements. We have provided this list of potential commercial vessel sewage pumpout options as a resource for commercial vessel operators.

Type I or Type II devices

Vessels with these MSDs must secure the devices to prohibit the discharge of sewage per 33 CFR 159.7(b) while in the NDZ.

The vessel operator must secure each device in a manner which prevents discharge of treated or untreated sewage. 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.
  • Locking the door to the space enclosing the toilets with a padlock or door handle key lock.

Without installed toilets 

Vessels without installed toilets must dispose of any collected sewage from portable toilets or other containment devices at facilities in a manner that complies with state law (ashore in proper facility).


Our approach is first focused on outreach and education. We are working with partners in an NDZ Enforcement Committee and NDZ Outreach and Education Committee on enforcement provisions and outreach and education.

However, it's the law. Your MSD may be inspected and you could be fined (Chapter 90.48 RCW, Chapter 173-228 WAC).  Ecology and the United States Coast Guard may enforce this rule by using the enforcement provisions in Chapter 90.48 RCW or other federal provisions. In addition, other federal, state, and local agencies may provide enforcement, as authorized.