On Thursday, September 3rd, we conducted RiverWatch Water Quality Monitoring at 10 long-term monitoring sites on the North and South Rivers with citizen science volunteers. This was our last sampling of 2026. Throughout the summer, we posted our bi-weekly water quality results on our website, social media, and in our e-news. You can use the search bar on https://www.nsrwa.org/ to find individual bi-weekly reports. Thank you to all of our volunteers this summer for conducting the sampling and analysis, the Cohasset Center for Student Coastal Research (CCSCR) for allowing us to use their laboratory for sample processing, and our members, MassBays, and MassDEP for providing funding for this program
We share this data with the public with a few important caveats; we are not a regulatory agency and these data are only a snapshot of the water quality at the time they were taken. Rain and other polluting events can impact the quality of the water at any time. For example, please take note that these results represent conditions on 9/3 following heavy rain earlier in the morning.
The purpose of the RiverWatch Water Quality Monitoring program, which began in 1994, is to determine whether or not the sites along the North and South Rivers have exceeded bacterial colony concentration numbers for Massachusetts’ swimming and shellfishing standards. We use these data to document the long-term health of our waters, to inform government agencies on the quality of our waters and advocate for improvements where needed.
Enterococcus samples were collected at ten sites along the North and South Rivers, while fecal coliform samples were collected in five shellfish growing areas (none of which are open at the moment for harvest). According to Massachusetts’ swimming standards, Enterococcus levels may not exceed 104 cfu per 100mL of water sampled. The Mass. Division of Marine Fisheries shellfishing standard is 14 cfu per 100mL of fecal coliform.
For samples collected on September 3, 2026, enterococci bacteria levels passed Massachusetts’ swimming standards at six of the 10 locations. Washington St. Bridge, Corn Hill Lane, Union St. Bridge, and Keville Foot Bridge exceeded the standards.
Additionally, fecal coliform concentrations exceeded the shellfish standard at all tested sites except for the mouth of the North River at 4th Cliff. Please note that all shellfish beds in the North and South Rivers are closed from May 31st until November 1st.
This was our sixth and final round of sampling for 2026. Please check our website and e-news for a seasonal summary in the coming weeks. Thank you to all of our volunteers this summer for conducting the sampling and analysis, the Cohasset Center for Student Coastal Research for allowing us to use their laboratory for sample processing, and our members, MassBays, and MassDEP for providing funding for this program
