No Discharge Areas (NDAs)
A "No Discharge Area" or "NDA" is a federally designated body of water where the discharge of both treated and untreated boat sewage is prohibited. Federal Law prohibits the discharge of untreated sewage from vessels within all navigable waters of the United States , which includes waters within three miles of shore.
- Within No Discharge Areas, only Type III marine sanitation devices may be used. A Type III MSD is a device that prevents the overboard discharge of treated or untreated sewage or any waste derived from sewage. It is typically a holding tank, but may include other types of technology including incineration, recirculation, and composting.
- Outside of No Discharge Areas, boats may discharge treated sewage through a functional Type I or Type II marine sanitation device
Federal Law provides a process for states to regulate vessel sewage discharges through application for the federal designation of No Discharge Areas. The DEP applied to USEPA for designation of certain areas as No Discharge Areas due to the nature of the areas, the environmental resources affected by pollution, and the number of vessels that frequent the areas.
NOTE: Maine has also enacted legislation that controls the discharges of combined sewage and gray water from large commercial passenger vessels. Gray water is the water from sinks and showers. This legislation is unique to Maine and, in combination with No Discharge Areas, results in waters that receive the highest regulatory protection in the United States . More information about Maine's commercial passenger vessel program.
- Pam Parker 207-485-3038
Currently Approved No Discharge Areas in Maine
- Casco Bay 2006: Final application; map
- Boothbay Region 2009: Final application; map
- Kennebunk-Wells 2009: Final application; map
- Southern Mount Desert 2009: Final application; map
- West Penobscot Bay 2009: Final application; map
- NDA Fact Sheet (pdf)