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Water: Outreach & Communication

Managing Nonpoint Source Pollution from Boating and Marinas

Pointer No. 9

epafiles_misc_outdatediconNote: This information is provided for reference purposes only. Although the information provided here was accurate and current when first created, it is now outdated.


Millions of people regularly enjoy recreational boating, and more than 10,000 marinas dot the coastline and waterfront property of North America. Because boats operate and are maintained directly in the water or near the shore, the growing number of recreational boaters and marina managers must take special care to manage activities that cause water pollution.

Individual boats and marinas usually release only small amounts of pollutants. Yet, when multiplied by thousands of boaters and marinas, they can cause distinct water quality problems in lakes, rivers, and coastal waters. The U.S. Environmental Protection Agency has identified the following potential environmental impacts from boating and marinas: high toxicity in the water; increased pollutant concentrations in aquatic organisms and sediments; increased erosion rates; increased nutrients, leading to an increase in algae and a decrease in oxygen (eutrophication); and high levels of pathogens. In addition, construction at marinas can lead to the physical destruction of sensitive ecosystems and bottom-dwelling aquatic communities.

Water pollution from boating and marinas is linked to several sources. They include poorly flushed waterways, boat maintenance, discharge of sewage from boats, storm water runoff from marina parking lots, and the physical alteration of shoreline, wetlands, and aquatic habitat during the construction and operation of marinas.

Proper marina planning and an informed boating public will limit pollution from these sources, promote long-term economic benefits and environmental health, and help recreational boating to remain a fun-filled outdoor experience. Clean boats, clean boating habits, and clean marinas benefit the entire boating community as well as aquatic life.

Managing Boat Operation and Maintenance

When caring for boats, a significant amount of solvent, paint, oil, and other pollutants potentially can seep into the ground water or be washed directly into surface water. The chemicals and metals in antifouling paint can limit bottom growth. Many boat cleaners contain chlorine, ammonia, and phosphates -- substances that can harm plankton and fish. Small oil spills released from motors and refueling activities contain petroleum hydrocarbons that tend to attach to waterborne sediments. These persist in aquatic ecosystems and harm the bottom-dwelling organisms that are at the base of the marine food chain.

There are several ways boaters can reduce pollution from boats and marinas. They can select nontoxic cleaning products that do not harm humans or aquatic life. Using a drop cloth, cleaning and maintaining boats away from the water, and vacuuming up loose paint chips and paint dust prevent paint and other chemical substances from entering waters. Carefully fueling boat engines, recycling used oil, and discarding worn motor parts into proper receptacles can prevent needless petroleum spills. Draining water out of all waterlines and tanks during winter freezes eliminates the possibility of bursting pipes. And perhaps most important, keeping boat motors well-tuned prevents fuel and lubricant leaks and improves fuel efficiency. These guidelines not only can keep water clean, but also can keep boats running smoothly.

Managing Boat Sewage and Waste

Often underestimated or ignored by the public, the discharge of sewage and waste from boats, can degrade water quality (especially in marinas with high boat use). Fecal contamination from the improper disposal of human waste during boating can make water unsightly and unsuitable for recreation, destroy shellfishing areas, and cause severe human health problems. Sewage discharged from boats also stimulates algae growth, which can reduce the available oxygen needed by fish and other organisms. Although fish parts are biodegradable, when many fish are gutted and cleaned in the same area on the same day, a water quality problem can result. Like raw sewage, excess fish waste can stimulate algae growth.

Boaters should attempt to achieve zero discharge of all sewage into recreational waters. While on the boat, fecal matter and other solid waste should be contained in a U.S. Coast Guard-approved marine sanitation device (MSD). Upon return to shore, portable toilets should be emptied into approved shoreside waste handling facilities, and MSDs should be discharged into approved pumpout stations.

Managing Siting and Design for Marinas

The siting and design of marinas are two of the most significant factors impacting marina water quality. Poorly planned marinas can disrupt natural water circulation and cause shoreline soil erosion and habitat destruction. To reduce activities that cause NPS pollution, marinas should be located and designed so that natural flushing regularly renews marina waters. In addition, predevelopment water quality and habitat assessments should be conducted to protect ecologically valuable areas. Grass and ground cover planting or, where necessary, structural stabilization measures can help prevent erosion during and after marina construction. Stormwater runoff can be controlled by implementing pollution prevention strategies and properly containing hull maintenance areas. Marina fueling and sewage collection stations should be maintained and designed to make cleanup of spills easier. When completed, the final marina design should deliver the most desirable combination of marina capacity, services, and access, while minimizing environmental impacts and onsite development costs.


Additional fact sheets in the Nonpoint Pointers series (EPA-841-F-96-004)

Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters, Chapter 5 (EPA-840-B-92-002)

Recreational Vessel Sewage Discharge Control: A Primer for State and Local Outreach Campaigns(EPA-842-B-94-005)

The Quality of Our Nation's Water: 1994 (EPA-841-S-95-004)

Water Watch: What Boaters Can Do To Be Environmentally Friendly, National Marine Manufacturers Association, Washington, DC

To order any of the above EPA documents call or fax the National Center for Environmental Publications and Information.

Tel (513) 489-8190

Fax (513) 489-8695


The State Organization for Boating Access, Washington, DC

Tel: (202) 944-4987

National Marine Manufacturers Association, Washington, DC

Tel: (202) 944-4985

Sea Grant college or university in your state

U.S. Environmental Protection Agency

Nonpoint Source Control Branch

Washington DC 20460


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