Don’t scrub-a-dub in the lake: Consider water health when cleaning boats

Imagine pulling up to your favorite cove on a warm summer afternoon. The lake is sparkling, the cooler is full, and the kids are already splashing around. As you hop in for a swim, your hand brushes against the side of your boat, and you feel that slick, greenish-brown layer clinging along the waterline. It’s like finding “wash me” scrawled through the dirt on your car window. Only this time, it’s your boat, and the temptation is there to grab some soap and scrub it clean while you’re already in the water.

While it may seem harmless, washing your boat while it is in the lake is both harmful to the ecosystem and prohibited under New Hampshire law. When boats are scrubbed or soaped up in the water, pollutants such as detergents, waxes, oils, and even microscopic invasive species can enter new areas of the lake. Many soaps and boat cleaning products, including those marketed as “marine-friendly,” contain phosphates, surfactants, dyes, and solvents. When these wash into the lake, they contribute to excessive plant and algae growth, degrading water quality and creating conditions that fuel harmful blooms.

Even products that are labeled as “green” or “biodegradable” are not necessarily safe. A study conducted by the Boat U.S. Foundation tested 20 cleaning products marketed as environmentally friendly. Many of those products turned out to be among the most toxic to aquatic life despite their claims. There are currently no federal requirements or standards for using the terms “biodegradable” or “environmentally safe” on product labels. Even products with the Environmental Protection Agency’s Safer Choice logo only include ingredients that have been screened for certain hazards; they are not specifically tested for aquatic toxicity.

Beyond the environmental risks, washing a boat in Lake Winnipesaukee or any New Hampshire waterbody violates state law. Under RSA 485-A:13, it is illegal to discharge waste, including wash water, antifreeze, or detergents, into surface waters or groundwater without first obtaining a permit from the New Hampshire Department of Environmental Services. Both boat owners and marinas are responsible for ensuring that cleaning and maintenance practices do not pollute state waters.

The best approach is to clean boats on land, at facilities designed to collect and properly treat wastewater. Many marinas have designated wash stations with pollution prevention programs, and a commercial car wash is another good option at the end of the season. If you need to remove surface grime mid-season, use only lake water and avoid soaps or cleaners altogether. A bilge sock, which absorbs oil and fuel residues before bilge water is pumped out, is another inexpensive way to reduce pollution.

The same considerations apply when rinsing off paddleboards, kayaks, pets, or yourself near the lake. Taking the extra time to prevent chemicals and waste from entering the water protects fish and wildlife, reduces the risk of algae blooms, and helps keep Lake Winnipesaukee clean and healthy during the busiest time of year.

The Lake Winnipesaukee Alliance encourages everyone to do their part by washing boats and gear responsibly, keeping pollutants out of the water, and practicing clean, drain, dry habits to prevent the spread of invasive species. 

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Bree Rossiter is the conservation program manager for the Lake Winnipesaukee Alliance. She manages the water quality monitoring program, cyanobacteria monitoring initiatives, the Winni Blue/LakeSmart program, and assists with watershed management planning efforts. Bree can be reached at brossiter@winnipesaukee.org. The Lake Winnipesaukee Alliance is a nonprofit dedicated to protecting the water quality and natural resources of the lake and its watershed. To learn more, visit winnipesaukee.org.