Hide Alert

Welcome to our new website. Learn more about what's new.

Frequently asked questions

These are some of the frequently asked questions we have received. For more information please see the main No Discharge Zone webpage or contact the project lead below. 

1. What is a No Discharge Zone (NDZ)?

A no discharge zone (NDZ) is a designated body of water where the discharge of sewage (blackwater/toilet waste) from boats, whether treated or not, is prohibited.

Under existing federal regulations, treated sewage may be discharged anywhere in Puget Sound, and untreated sewage may be discharged as long as the boat is more than three miles from shore.

If an NDZ is established no boat of any kind or size could discharge anywhere within the zone. All boats and vessels would have to store their sewage until they could safely dispose of it at an onshore or mobile pumpout facility, or hold it until it can be discharged in the open ocean beyond three miles from shore. The United States Environmental Protection Agency (EPA) Vessel Sewage website has more information on NDZs. There are more than 90 NDZs in 26 states. A full listing of these NDZs is provided on EPA’s NDZ website. Washington has no NDZ.

​2. When will a No Discharge Zone take effect?

An NDZ will take effect after planned rulemaking is complete. Until then, vessels can continue to operate by current discharge requirements. This includes no discharge of untreated sewage within 3 miles of shore. EPA reviewed our petition and determined that a no discharge zone can be established for Puget Sound. EPA found that there are adequate facilities in the Puget Sound for vessels to pump out their sewage and Washington State may move forward with a designation. With EPA’s approval in place, we will be initiating rulemaking to make Puget Sound off limits to vessel sewage.

3. Which waters will be included in the No Discharge Zone?

The NDZ boundaries in the submitted petition include all inland marine waters of Puget Sound, Lake Washington, and all the water bodies that connect Lake Washington to Puget Sound. The proposed NDZ would apply to all recreational and commercial vessels. The proposed NDZ boundary would include the marine waters east of a line between the New Dungeness and Discovery Island lighthouses, east of Port Angeles and Victoria. This would include the San Juan Islands in the north and South Puget Sound and the Hood Canal.

4. Why can't we rely on Marine Sanitation Devices to treat boat waste?

The performance of most commonly used marine sanitation devices (MSDs) is inadequate for treating sewage or for ensuring the protection of Puget Sound. An EPA study documented that fecal bacteria levels in discharge from approved MSDs can be several thousand times higher than Coast Guard standards for MSDs.

The MSDs typically only grind up and disinfect the waste, and lack the ability to effectively treat organics, solids, toxics and nutrients. Establishment of an NDZ will ensure that waste discharges from vessels do not continue to contribute to the degradation of Puget Sound.

5. What do MSDs do?

There are three types of MSD, and each works differently:
  • Type 1: Grinds and disinfects sewage, and should control fecal bacteria to 1,000 bacteria per 100 milliliters of water.
  • Type 2: Digests sewage with a septic process, and should control fecal bacteria to 200 bacteria per 100 milliliters of water.
  • Type 3: Provides a holding tank for disposal of sewage other than to water, most commonly by pump-out for delivery to an on-shore wastewater treatment plant.

6. How do Type 1 and 2 MSD discharges compare to on-shore treatment?

There are several differences:
  • Studies on MSD treatment show an average of 2 million fecal coliform for type II MSDs and a simulated study shows an average of 82 fecal coliform for type I MSDs, although likely higher in real world conditions; the water quality standard for most of Puget Sound is a geometric mean of 14 with no more than 10 percent higher than 43.
  • On-shore plants must limit bacteria to meet the water quality standards at a fixed deep water outfall already closed off for shellfish harvesting. On-shore treatment typically average around 20 fecal coliform (15 for the Mukilteo plant in 2016).
  • On-shore treatment plants must monitor their discharges and ensure their process performs according to required standards.
  • There is no monitoring or maintenance required after an MSD is installed.

7. How would a Puget Sound NDZ affect boaters?

Recreational boaters with existing holding tanks will continue to hold their sewage (blackwater) within the NDZ area, and either pump out their sewage for treatment at an on-land wastewater treatment plant or discharge outside of the NDZ and beyond 3 miles. Recreational boaters with Type I or Type II MSDs will need to add a holding tank and not discharge any treated or untreated sewage in an NDZ.

Commercial vessels will also have to hold their sewage, treated or untreated, while in an NDZ and either pump out their sewage for treatment at an on-land wastewater treatment plant or discharge outside of the NDZ and beyond 3 miles or outside of the NDZ with a certified Type II MSD.

8. With so many vessels with holding tanks, why is an NDZ necessary?

Parts of our marine waters are more than three miles from shore. Without an NDZ vessels can discharge sewage in these areas. Also, some commercial and recreational vessels have type II MSDs which typically do not treat sewage to the same standards as land-based systems and are not well maintained or operated. The poorly treated or raw sewage discharged from vessels on Puget Sound puts water quality and public health at risk. Without an NDZ, only the U.S. Coast Guard has jurisdiction for vessel sewage regulation and enforcement, but has few resources for this. With an NDZ, enforcement can occur at a local level.

9. What about graywater?

The NDZ does not affect graywater discharges. The Clean Green Boating website has information on best management practices and requirements for graywater, as well as other potential discharges such as fueling, bilge care, and hull cleaning.

10. Why should there be a ban on vessel sewage when Victoria dumps raw sewage?

Vessel discharges occur at the surface and the movement of Puget Sound surface currents connects vessel pollutants to sensitive resources. Even though, in Canada, local and provincial governments are still in the process of improving Victoria area sewage treatment, vessel sewage in Puget Sound is a separate concern.

11. How much does it typically cost to pumpout my vessel?

Most recreational pumpouts are either free or $5. Mobile pumpouts boats may charge more for the convenience of coming to you. Commercial vessel pumpout costs vary, typically to cover the cost of sending the sewage to land-based treatment.

12. How has Ecology evaluated whether or not an NDZ is needed?

Over the last five years, Ecology has been evaluating the appropriateness and feasibility of establishing an NDZ in all or parts of Puget Sound. Although not required by EPA for an NDZ petition, Ecology's work has produced more than nine reports on various topics such as vessel populations and sewage management, Puget Sound conditions and modeling, pumpouts, cost/benefit, and implementation strategies. Ecology has also reached out extensively to stakeholders and provided a draft petition, and obtained input in 2014.

13. Where did this idea come from?

Establishing an NDZ is a near term action on the Puget Sound Partnership's Action Agenda and is highlighted in the Washington Shellfish Initiative. Ecology has researched and prepared the NDZ petition with a grant from the Washington Department of Health, funded by EPA’s National Estuary Program.

14. How would the government implement the NDZ?

Ecology and other agencies would emphasize education for vessel owners and operators. The current effort to provide pump-out resources would continue and the number of pumpout stations would increase. Ecology is offering grants funds to provide commercial-scale pumpout facilities in key port areas. These outreach and education efforts would be supported by the development of enforcement mechanisms among agencies that patrol waterways in the zone.

15. How does a vessel operator comply with an NDZ?

The requirements for vessel operators are described in 33 CFR 159.7(b)-(c) (PDF) (2 pp, 190 K). The regulations allow for four methods of securing a Type I or II marine sanitation device (MSD) while in an NDZ, including:
  • 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.
For Type III devices, the following options are available:
  • Closing valves leading to overboard discharge and removing the handle;
  • Padlocking any valves leading to overboard discharge in the closed position; or
  • Holding overboard discharge valves closed using a non-releasable wire-tie.

16. Why is Ecology asking vessels to withhold their sewage when King County is allowed to discharge raw sewage to Puget Sound?

King County is not allowed to discharge raw sewage from its West Point wastewater treatment plant and it is under a legal order to control its combined sewer/stormwater overflows.

The proposed Puget Sound no discharge zone for vessel sewage is a pollution-prevention effort and will help protect shellfish areas and swimming beaches. On-board vessel treatment systems do not achieve the level of treatment that on-land wastewater plants must provide. In addition to its treatment plant permits, which set pollution limits on its discharges, King County is under a legal requirement (consent decree) to correct combined sewer/stormwater overflows and minimize their discharges into Puget Sound.