Charles River Water Quality Earns an A- for the Second Time in the Past Five Years

The EPA has given the Charles River a grade of “A-” for bacterial water quality in the river during 2017. This is only the second time the river has earned a grade as high as an “A-minus,” and both have occurred within the past five years.

“The Charles River turnaround is a perfect example of what strong partnerships with States, Municipalities, and Non-Profit organizations can achieve,” said Alexandra Dunn, regional administrator of EPA’s New England office. “EPA continues to work hard at improving water quality in the Charles River by tackling pollution sources by detecting illicit discharges and our work on combined sewer overflows. EPA is also protecting this great resource with stormwater permits that address the problem of nutrient pollution.”

The EPA grade for water quality in the lower Charles River is based on bacterial sampling conducted by the Charles River Watershed Association (“CRWA”) over the 2017 calendar year. CRWA collects monthly water quality samples at ten monitoring sites from the Watertown Dam to Boston Harbor.  In 2017, the Charles was meeting the state’s bacterial water quality standards for boating 95 percent of the time, and for swimming 72 percent of the time. This is the 23rd year EPA has issued a Charles River Report Card.


The Charles River grade is determined by comparing the amount of time the river meets water quality standards to the following criteria:

A – almost always met standards for boating and swimming
B – met standards for almost all boating and some swimming
C – met standards for some boating and some swimming
D – met standards for some boating but no swimming
F – did not meet standards for boating or swimming

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