Even when treated, boat sewage still contains significant amounts of harmful sewage bacteria, nitrogen and toxic chemicals used to treat the sewage, so even discharge of treated sewage can harm water quality and aquatic organisms like fish, marine mammals, birds, turtles and invertebrates. NDAs help to keep the water in our swimming beaches and shellfish beds clean and free of pollutants from boat sewage discharges. NDAs also help our coastal economy which relies on clean waters for swimming, boating, fishing and tourism.
APCC has led the effort to protect the Cape's coastal waters as No Discharge Areas (NDAs) for boat sewage, beginning with the Cape Cod Bay No Discharge Area designation in 2008 and ending with South Cape Cod and the Islands No Discharge Area designation in 2012. APCC staff participated in the Cape Cod Bay and South Cape Cod and the Islands NDA Working Group, which pushed for NDA designations, collected information on numbers of boats and pumpouts, helped to write the applications, encouraged state and federal officials to proceed with the nominations, supported state legislation strengthening the ability of local and state harbormasters and law enforcement officials to enforce NDA rules, helped the towns of Dennis and Provincetown to obtain funding for boat pumpouts, and urged local officials and citizens to support the nominations. APCC has also supported NDA designations by other groups throughout the Cape.
The federal Clean Water Act allows communities and states to nominate water bodies as No Discharge Areas in order to protect water quality against the harmful effects of boat sewage. No Discharge Areas, or NDAs as they are called, are water bodies where the discharge of any and all boat sewage, whether treated or not, is prohibited.
Within an NDA, boats must hold their sewage until they reach a pumpout facility where the sewage can be pumped out and sent to a municipal wastewater treatment facility for treatment. Wastewater treatment facilities are able to treat the sewage to a much higher—and safer—degree of cleanliness than boat marine sanitation devices, or MSDs.
This figure shows why treated boat sewage can still contain too many harmful bacteria relative to water quality standards. This chart compares the treatment standards for sewage bacteria in marine toilets (MSDs) with water quality standards for beaches and shellfishing waters. The red columns show how many harmful bacteria are allowed to remain in sewage treated with MSDs. The blue columns show the water quality standards for shellfishing waters and for swimming beaches.
Portions of the waters of Cape Cod and the Islands were nominated and designated as NDAs beginning in 1992. These included Nantucket Harbor (1992), Waquoit Bay (1994), Wellfleet Harbor (1995), Stage Harbor in Chatham (1997), Harwich (1998), Buzzards Bay (2000), and Three Bays/Centerville Harbor (2001). However, as of 2007, there were large gaps in protection as shown by the map of NDAs in Massachusetts as of 2007.
In 2008, the Cape Cod Bay No Discharge Area was nominated and designated. This was the largest NDA area added at that time, accompanied by smaller NDAs in the South Shore and North Shore areas.
In 2011, the waters of the Outer Cape were designated as NDAs, providing protection for coastal Atlantic waters of the Cape.
As of July 12, 2012, Massachusetts reached a major milestone in protecting our coastal waters from boat sewage. On that date, the South Cape Cod and Islands No Discharge Area was designated, closing the largest remaining gap in protection in the state. This NDA includes a huge area of coastal waters south of Cape Cod and surrounding Nantucket and Martha's Vineyard, including Aquinnah, Chilmark, West Tisbury, Tisbury, Oak Bluffs, Edgartown, Falmouth, Mashpee, Barnstable, Yarmouth, Dennis, Harwich, Chatham, and Nantucket. With this designation and that of Mount Hope Bay, all of Massachusetts coastal waters are now protected from discharge of boat sewage.
The help of the boating public is still needed to make these NDAs work. Boaters need to know the rules and use the pumpouts that are provided. For general information on NDAs, visit the EPA website. For information on pumpout locations, an interactive map of pumpouts, and other useful local information, visit the MA CZM website. Finally, support your local wastewater treatment facility that receives boat sewage for treatment.