Background and Studies on Impacts of Underwater Hull Cleaning

Resources for Professional Divers

The Clean Water Act prohibits the discharge of any pollutants into surface water. Marine facilities that wash boat bottoms painted with antifouling paints must have a General Permit for Discharges from Marinas from the Maryland Department of the Environment, which prohibits the discharge of boat bottom wash water that does not meet strict limits on dissolved metals (copper, zinc, lead) as well as oil/grease and total suspended solids. The General Discharge Permit specifically prohibits the cleaning of soft ablative paints in the water.

While the General Discharge Permit does not specifically apply to divers, the Maryland and federal law do not allow the release of pollutants from any source into surface water. Professional divers need to use best management practices to prevent releasing paint and metals.

The University of California Sea Grant Extension Program has researched the many issues surrounding antifouling bottom paints for many years. Their website offers some of the most comprehensive research on these topics and includes an excellent video. Divers, boat owners, and those who apply bottom paint are strongly encouraged to visit the site below, and learn more about this complex topic.