How to Best Manage Graywater in Puget Sound

Become a steward of the environment by following some of these simple tips every time you hit the water this season.

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Words by Blair Englebrecht

Recreational boaters in the Pacific Northwest have the privilege of enjoying some of the most captivating environments in the region. There’s nothing quite like catching fresh salmon under the towering Olympic Mountains, or being amongst the San Juan Islands as orcas, otters and other marine life gracefully appear above and below the water’s surface.

Boaters, too, are a part of the seascape as they immerse themselves in the quiet wonder of Puget Sound. With this privilege comes on how best to protect the Sound from the excesses of boating – particularly when it comes to graywater.

The International Maritime Organization defines greywater as ‘the drainage from dish, shower, laundry, and bathwater, as well as the excess from wash bin drains.’ Surprisingly, the harms of graywater are remarkably similar to those of sewage. While the Puget Sound No Discharge Zone prohibits blackwater discharges, it doesn’t apply to graywater. Yet, the U.S. Environmental Protection Agency (EPA) reports that untreated graywater has similar characteristics to domestic sewage and can have higher concentrations of certain contaminants.

For example, there is one to three times higher fecal coliform concentrations in untreated vessel graywater than untreated domestic wastewater. Graywater also contains harmful chemicals, pathogens, bacteria, metals, food waste, and problematic nutrients and discharges can lead to depleted oxygen levels, increased amounts of bacteria as well as nutrients in the surrounding ecosystem.

Consequently, higher nutrient concentrations can cause harmful algal blooms and dead zones, which can result in damaging disruptions in the already-fragile Puget Sound food chain. Contaminants found in graywater impair the health of many species including the vital Chinook salmon, the main food source for southern resident orcas.

As Chinook salmon become scarcer due to factors like poor water quality and the buildup of toxins in their systems, orcas are increasingly faced with a scarce amount of prey and reproductive issues due to the biomagnification of toxins that are found in the salmon.  Of equal concern is when those toxins wind up on our dinner plates in the fish we enjoy from the region.

While the contamination of aquatic life doesn’t come solely from recreational boaters can certainly practice risk reductions to help ensure our vulnerable communities’ livelihoods, health, and cultures are protected.

The Clean Marina Washington program recommends becoming with the applicable rules and regulations while following the best management practices to ensure your vessel leaves a healthy wake. 

Rules and Regulations

  1. When it comes to hull cleaning and maintenance for vessels, the use of antifouling paint is prohibited. Vessel owners using antifouling/ablative paint who want to clean their hull must haul out and transport it to a permitted boatyard facility (RCW 90.48).
  2. Using any soap or detergent for boat cleaning, even if – its labeled biodegradable – is prohibited. No cleaner meets the legal requirements to enter Washington waters. While anecdotal wisdom says that vinegar is ok, it’s still detrimental to water quality and should not be discharged. Vessel owners who want to wash their boat with any type of detergent should do so at a designated boat wash on shore with a proper filtration system. Any turbidity, sheen, or discoloration of the water is considered a violation of Washington State Law (RCW 90.48).
  3. The use of soap as an oil/fuel dispersant is prohibited. While soap makes the sheen go away, it actually causes oil to sink and become unrecoverable. If you create or observe a spill, report it immediately to Washington Emergency Management at (800) 258-5990 or (800) OILS-911, and the U.S. Coast Guard’s National Response Center at (800) 424-8802. You may also report to Puget Soundkeeper’s Pollution Prevention Hotline at 1-800-42PUGET.

Best Management Practices

1.      Reduce and Dispose of Graywater

  • Limit the generation of graywater by utilizing shoreside facilities for showers, laundry, and dishwashing.
  • Rather than discharging graywater, contain it on board and transport it to a self-serve pump-out station or use a pump-out service if one is available to you.
  • If you must discharge graywater, do so at least one nautical mile away from shore.

2.      Minimize the Impact of Graywater

  • Do not drain cooking oils into your graywater system.
  • Scrape and wipe food and oil residue from dishes as much as possible before placing dishes in a washing machine or sink water that will be discharged with graywater.
  • If boaters are unable to use shoreside facilities for showers and dishwashing, use EPA Safer Choice labeled products. A complete list of approved products can be found at www.epa.gov/saferchoice.
  • Encourage your local retail marine outlet or marina chandlery to carry EPA Safer Choice products so they are easily accessible.
  • Use sink screens or strainers and dispose of any strained waste in the garbage.
  • If vessel owners keep plants on board or on deck, don’t use any fertilizers, herbicides, or pesticides for upkeep, and always use containment under planters/pots.

3.      Reduce Boat Maintenance impacts

  • If possible, perform any maintenance that requires the use of hazardous materials (paint, varnish, etc.) at a permitted shoreside boatyard facility. In-water maintenance is allowed only for minor touch-ups of the superstructure, deck, and hull above the waterline. Also be sure to use extreme caution, place a tarp over the work area, clean up and dispose of all debris, and contact your marina office for additional containment provisions such as absorbent pads or sausages.
  • When feasible, engine maintenance should be carried out at a permitted boatyard facility. Check with your marina to ensure routine/minor engine maintenance is permitted. Any on-water maintenance should be done by a professional with all necessary precautions employed. Ask your marina for absorbent pads or sausages to contain the maintenance area. Do not store oils or fuels in open containers on deck, and only have the amount needed for the work.
  • Always check your bilge for oil sheen/turbidity before operating the bilge pump. If there is a sheen or turbid water, ask your marina for advice on how best to dispose of the contaminated water. Do not use a self-serve pump out for bilge water.

By following these best practices, you’ll not only be contributing to maintaining the purity of Puget Sound, but you’ll be setting an example for others to follow and spreading the message of the importance of keeping the waterways clean and healthy.  More information on clean boating practices can be found at www.cleanmarinawashington.org, which includes a list of certified Clean Marinas who employ these practices.

Blair Englebrecht is the Boating Programs Manager for The Puget Soundkeeper Alliance.