Watershed groups seek to intervene in court proceedings following MWRA’s proposal to dump more sewage in Charles and Mystic Rivers (Press Release)

FOR IMMEDIATE RELEASE: November 19, 2025
Contact: Stefan Geller, Senior Communications Manager

BOSTON, MA – Three weeks after the Massachusetts Water Resources Authority (MWRA) proposed a plan that would allow for untreated sewage to continue to be dumped into the Charles and Mystic Rivers forever, making people sick and destroying sensitive ecosystems, watershed groups filed a motion in court on Tuesday to intervene in the ongoing federal lawsuit that led to the cleanup of Boston Harbor.

“MWRA has laid its cards on the table with its recent proposal. Despite all the promises made, officials have made it abundantly clear that they have no intention of ridding the Charles River of sewage, as they are legally required to do,” said Emily Norton, Executive Director of Charles River Watershed Association (CRWA). “We need a seat at the table in the federal case, where decisions are going to be made about how to deal with MWRA’s failure to comply with its current obligations to reduce CSOs.”

Combined sewer overflows, or “CSOs”, are a key source of pathogen contamination to the Charles and Mystic Rivers and are becoming more frequent as our climate changes. In these outdated sewer systems, stormwater and household/industrial wastewater are collected in the same pipes to be conveyed to a wastewater treatment plant, but during heavy rainstorms, the combined system cannot handle the excess polluted water and it is released into the rivers.

Under the ongoing federal lawsuit that led to the cleanup of Boston Harbor, MWRA is legally required to carry out an extensive effort to reduce sewage discharges into the Charles and Mystic, but hasn’t achieved the required levels of CSO control, years past the deadline. MWRA has signaled that it would like to declare “mission accomplished,” but the judge has instructed the MWRA, EPA, MassDEP and Conservation Law Foundation to work together toward a resolution. 

“The Boston Harbor cleanup case brought the promise of swimmable, fishable waters in Greater Boston,” says Patrick Herron, Executive Director of the Mystic River Watershed Association (MyRWA). “MyRWA is joining the motion to intervene alongside the Charles River Watershed Association because this promise has yet to be fulfilled. This is particularly damaging upstream in our river systems and in tributaries like Alewife Brook. We hope to work with the existing parties towards practical solutions that improve water quality and public health for the benefit of all of our community members.”

At the same time, the watershed associations have been actively participating in the process to develop an updated CSO control plan for the Charles and Mystic Rivers. Hundreds of residents have participated in this process and asked MWRA to stop dumping sewage in these rivers. Yet during an October 29 meeting with its Board of Directors, MWRA staff recommended a plan that would increase sewage discharges in the coming years, and downgrade the water quality classifications of the Charles and Mystic Rivers.

Given deep concerns that MWRA’s recent proposal signals that the Authority has no intention of making further meaningful efforts to reduce and eliminate CSOs, CRWA and MyRWA have asked the court to be added as parties to the case in order to have a say in how the issues get resolved.

"CRWA and MyRWA and their members have undeniable and compelling interests in the outcome of the current federal litigation. More importantly, they bring a level of expertise and experience to the case that will aid in a fair resolution that moves these iconic rivers closer to being free of CSO discharges," said Kevin Cassidy, Senior Attorney for Earthrise Law Center, the environmental legal clinic of Lewis & Clark Law School, which is representing CRWA and MyRWA.

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Charles River Watershed Association’s mission is to protect, restore, and enhance the Charles River and its watershed through science, advocacy, and the law. CRWA develops science-based strategies to increase resilience, protect public health, and promote environmental equity as we confront a changing climate.

Mystic River Watershed Association builds solutions so that all people across the watershed, no matter who you are or where you live, have safe and easy access to nature and a healthy environment. MyRWA is rooted in science and the understanding of environmental injustices. We believe access to information and opportunities to learn about the natural world empower us all to work together for a better future in the Mystic.

Earthrise Law Center is the environmental legal clinic of Lewis & Clark Law School.