With beach season in full swing, Massachusetts waters are drawing more than just vacationers. Recent data show that high bacteria levels are threatening water safety at popular beaches in the state and nationally.
The number of beaches across the state that have failed bacterial tests has been on the rise in recent years, leading to the closure of popular swimming spots, a Globe analysis of newly released state data shows. The pollution stems from older sewer systems that carry sewage and storm water in the same pipes and can overflow after heavy rains.
Three of the worst years since records began in 2002 have occurred in just the last four years. Last year, the state reported a failure rate of 6.2 percent, the third highest ever, which was also well above the historical average of 4.7 percent, according to data from the state public health agency. Every year since 2018 has matched or exceeded the historical average.
Four sites failed a majority of all bacteria tests that were conducted from 2020 to 2024: one at a freshwater beach called Damon Pond in Ashby, two at a freshwater beach at Beaman Pond in Templeton, and one at Kings saltwater beach in Lynn.
The Cape boasts some of the state’s cleanest beaches. But two exceptions are Keyes Beach in Hyannis, which failed 26 percent of all tests from 2020 to 2024, and a testing point in western Provincetown that failed 21 percent of all tests.
Inland freshwater beaches had more sporadic results, where some near Baldwinville and outside of Ashby had very high violation rates, while others, like the Arlington Reservoir, rarely fail tests.
Unsafe levels of bacteria are not unique to Massachusetts. Environment America Research and Policy Center, an organization that works to protect America’s natural resources, released a Safe Swimming Report in July, allowing readers to look up bacteria levels at beaches nationwide. Representatives of the group’s Massachusetts chapter held a press conference this month at Constitution Beach to highlight results.
In Massachusetts, 58 percent of beaches had unsafe levels of bacteria, indicating fecal contamination, on at least one testing day last year, according to data from the National Water Quality Monitoring Council and analysis by Environment America. Massachusetts closes beaches that fail bacteria tests and reopens them when levels fall back to normal.
Massachusetts had the lowest percentage of potentially unsafe beaches in New England. Nationally, the East Coast fared pretty well: It had the second lowest unsafe beach rate after Alaska and Hawaii.
The sources of this bacteria are often sewer and storm water drainage. While newer systems separate sewage and storm water, some older cities still have so-called combined sewer overflows, which transport both of these flows in the same pipes.
“Heavy rains can overload sewage treatment plants, meaning that raw or partially treated sewage gets released directly into recreational waterways,” said Devon Bell, summer associate for Environment Massachusetts who also spoke at the press conference.
Additionally, as the climate warms, water warms as well, increasing bacteria proliferation, said John Rumpler, clean water director and senior attorney at Environment America.
Climate change has also led to an increase in the severity of rainstorms, leading to more intense rain and more flooding, also contributing to the overflow of sewage systems into waterways.
New legislation in Massachusetts is taking aim at the problem.
Three bills relating to sewage overflow were introduced in the Massachusetts Legislature this year. Bill H.1046 is of particular interest to Environment America, said Rumpler, since it aims to require water utilities to reduce the number of combined sewer overflows.
Two additional bills, H.1031, which focuses on waste water management related to combined sewer overflows, and S.608, which calls for the elimination of untreated combined sewage systems, were also presented this year.
“Nationwide, over 7,500 beach warnings or closures were issued due to contamination,” said Eric Magers, executive director of Seaside Sustainability, a nonprofit organization focused on protecting oceans. “These are not isolated events. They reflect systemic infrastructure failures and continued pollution of our waterways.”
Some beachgoers say they are concerned about water quality and build it into their habits.
Jessica Schettino and her friend Stacey Scapicchio, who were visiting Constitution Beach in East Boston on a recent day with their daughters, said they check for alerts about water quality and bacterial levels before coming, and stay away if the tests show conditions are poor.
Allowing their children into the water is always worrisome for them because they are aware that sewage overflows cause contamination. Both moms hope the new legislation will pass and make beaches safer.
“We have to get into the modern times and figure out how to live more sustainably with our ecosystems,” Schettino said.
Paul Barry, who lives in Brighton, also frequents Constitution Beach, where he enjoys swimming and reading on the beach. He, too, has encountered instances when the beach has been closed.
“You could visibly see the foam, a white foam floating in,” Barry said. “I didn’t go swimming that day, that’s just asking for trouble.”
Katarina Schmeiszer can be reached at katarina.schmeiszer@globe.com. Follow her on X at @katschmeiszer. Scooty Nickerson can be reached at scooty.nickerson@globe.com.