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U.S. v. Metropolitan District Commission, et al. (Boston Harbor) (D. Mass.)
Partial Chart of Boston Harbor in: The Atlantic Neptunepublication dates 1773-1784 by Joseph F. W. DesBarres. Courtesy of Treasures of the NOAA Library Collection

History of Contamination

Boston Harbor is the largest harbor serving a major city on the East Coast. It was the site of the Boston Tea Party in 1773. It has many developed and undeveloped islands, thousands of acres of marshes, tidelands, and fish bed, and many beaches and inlets. Many citizens swim, sail, and fish in and around the Harbor. However, by the mid-1980s, Boston Harbor was found to be the dirtiest harbor in the United States

Much of the contamination was the result of discharges from the woefully inadequate facilities for treating metropolitan Boston area sewage. These facilities were owned and operated until 1985 by the Commonwealth of Massachusetts, through its Metropolitan District Commission (MDC). The Commonwealth transferred responsibility for the management and operation of the facilities in 1985 to a newly created Commonwealth authority, the Massachusetts Water Resources Authority (MWRA). Other contamination resulted from combined sewers overflows (CSOs) before the sewage even reached the treatment facilities.

1985 Environmental Enforcement Section Files Action Under Clean Water Act

Following lawsuits brought by the City of Quincy in State court and the Conservation Law Foundation in federal court, the Environmental Enforcement Section filed an action under the Clean Water Act (CWA) in 1985 against the Commonwealth, the MDC, and the MWRA, alleging violations of the National Pollutant Discharge Elimination System (NPDES) permit issued to the Commonwealth and transferred to the MWRA.

At the time the lawsuit was filed, the sewage and storm water entering the treatment facilities received only primary treatment, consisting mostly of settling tanks. The waste that settled to the bottom of the tanks was sewage sludge. The liquid containing the sewage contaminants that did not settle out was discharged, after chlorination, into the Harbor. The sludge was also discharged into the Harbor twice a day at high tide.

In 1985, the federal district court ruled that the Commonwealth and MDC had violated the CWA and that the MWRA was liable for the violations as a successor to the Commonwealth and MDC. The presiding judge commented in his opinion that,

"As I delve into the record in this case it becomes more and more incomprehensible to me that the defendants have continually discharged the sludge back into the Harbor daily. By so doing, they virtually eliminate any benefit the initial treatment steps may have had. This simply amounts to separating water from filth, and pumping both back into the Harbor."

Subsequently, the Court entered an order requiring the MWRA to construct secondary treatment facilities.


  • During the 1990's, the MWRA constructed three batteries of secondary treatment facilities.
  • The Court has also entered numerous other orders over the years, usually on unopposed or joint motions for entry following negotiations, requiring the construction of sludge management facilities, an outfall extension, and CSO abatement projects.

    As a result, sludge is no longer discharged into Boston Harbor, and the now cleaner effluent from the MWRA's Deer Island treatment plant is discharged at a deeper and farther away location in Massachusetts Bay.

  • Design and construction of CSO abatement projects have been under way for a number of years and numerous projects have been completed. Others are scheduled for completion through the year 2015. There has been substantial litigation over the years relating to various components of the injunctive relief.
  • The penalties portion of the case was settled in 1988 and required the Commonwealth and MDC to pay a penalty of $425,000 and $2,000,000, respectively, into a trust for the performance of specified projects directed towards restoration of Boston Harbor and Massachusetts Bay.
  • In 2008, the Section filed an amended complaint, alleging that the MWRA had unlawfully bypassed its secondary treatment facilities on various occasions, during both wet weather and dry weather. The bypass allegations were settled in 2008. MWRA paid a civil penalty of $305,000 and is currently performing three supplemental environmental projects at an estimated total cost of $305,000.

Last Updated: October 2012