Pressure Washing Information

Even with a coat of bottom paint, most vessels need to have their hulls cleaned once a year to remove any biological growth. The most popular and efficient method is to power or pressure-wash the hull once the boat is hauled from the water by using a high-pressure stream of water over the boat bottom while the boat is situated over a travel-lift well or on a boat ramp. The resulting washwater contains fouling organisms and paint chips, and is usually discharged directly into the surface waters or allowed to soak into the ground. This wastewater, if not properly managed, may contaminate surface water and groundwater.

The state of Maine conducted a study in 2002 to determine what contaminants are in the bottom paint, washwater, and bottom sediments surrounding the wash area. The study was performed at boatyards and marinas with marine railways that typically perform pressure washing in the intertidal zone where washwater flows directly and into the water. The Maine study revealed that in addition to the expected high copper levels, lead levels were unexpectedly high. Here are the state's data:

Contaminant*	Paint Sanding Dust	Washwater	Bottom Sediment after washing	Bottom Sediment 5 months later
Copper	228-330,000 ppm (33%)	20-170 ppm	35,000 ppm (3.5%)	750 ppm
Lead	269-9,900 ppm	0.2-3.7 ppm	640 ppm	88 ppm
Zinc	~2,100 ppm	5.4-15 ppm	8,400 ppm	390 ppm
Background Levels: Copper - 0.028 ppm, Lead - 0.007 ppm, Zinc - 0.019 ppm

* For reference, standards for drinking water are: 1.3 parts per million (ppm) for Copper, 0.015 ppm for Lead, and 5 ppm for Zinc

These data and other studies on contaminants in pressure washwater demonstrate that treatment of this wastewater is necessary to meets state and federal discharge limits before discharging to coastal waters, sanitary sewers, or into the ground (groundwater).

Current Regulations
Most marinas or boatyards performing boat maintenance outdoors are required to have permit coverage under the National Pollutant Discharge Elimination System (NPDES) Stormwater Multi-Sector General Permit for Industrial Activities. To date, Massachusetts has not been delegated to administer this program. Therefore marinas in Massachusetts must follow the federal permit rules. The NPDES stormwater permit specifically prohibits the inclusion of pressure washwater in stormwater discharges. As a result, facilities need an individual NPDES permit, if the pressure washwater is discharged directly to coastal waters. If discharging onto a permeable surface, such as gravel, facilities need a groundwater discharge permit. A permit is also required for discharge to a sanitary sewer. Discharge to a septic system is prohibited. Regardless of the discharge option, these permits require significant pretreatment of the wastewater prior to discharge. All pretreatment systems (for discharge) likely need to be run by a state certified operator. In addition to the wastewater, some sludge and solid waste is generated, which will most likely be disposed as solid waste.

CZM Efforts
As part of a comprehensive effort to assist marinas in tackling this difficult issue, CZM awarded $12,500 each to Cape Ann Marina in Gloucester and Arey's Pond Boatyard in Orleans for the installation of treatment systems to remove pollutants from pressure washwater. In December 2004, each of these facilites hosted a demonstration event that allowed the general public, marina operators, and state officials to view the funded systems. Progress has been made since then and a number of facilities have installed washpads and wastewater treatment systems and many more have begun planning for systems.

In addition to these demonstration projects, and recoginizing that the pressure washing information in the Massachusetts Clean Marina Guide was not correct, CZM is developing a pressure-washing addendum to the Guide, which will discuss the issues, regulations, and strategies to address marine pressure washwater pollutants. Marinas will be able to use this document as guidance to implement effective solutions.

Please contact Robin Lacey if you have any questions about the demonstration projects, pressure-washing, or general environmental management questions related to clean marinas.

Robin Lacey
617-626-1220
robin.lacey@state.ma.us