2021 Water Quality Report Card

On Sunday, July 4, 2021 Save the Harbor/Save the Bay released its annual Water Quality Report Card for the Metropolitan Beaches from Nahant to Nantasket, using monitoring data from the 2020 beach season.

Weekly water quality testing at Boston’s regional beaches began in late May of 2020. Additional daily testing of Constitution Beach, King’s Beach, Malibu Beach, Tenean Beach, and Wollaston Beach began in early June and concluded on Labor Day weekend, September 6, 2020.

This chart summarizes the results:

These beach safety scores are calculated as the percent of water samples that comply with the Massachusetts Department of Public Health single sample limit for bacteria, a straightforward way to evaluate seasonal beach water quality and potential impacts on public health.

Rainfall can have a significant impact on beach water quality and can vary greatly from year to year. Changes in the summer storm intensity and frequency can often explain the variations we see; 2020 was a relatively dry year, with only a few large summer storms and relatively fewer wet weather impacts. It is also important to note that some beaches are tested daily, while others are tested weekly, so in some instances a single failed test can change the rating for that beach.

These seasonal variations are why Save the Harbor/Save the Bay is reluctant to draw conclusions from results for individual years, preferring to rely on multi-year averages.

In 2020, the overall water quality safety rating for Boston Harbor’s regional beaches managed by the Department of Conservation and Recreation was 93% which was an improvement over the prior year, which had a score of 89%. 

Five beaches had perfect scores of 100% in 2020, including Carson Beach, City Point and Pleasure Bay in South Boston, and Revere Beach and Winthrop Beach as well. Eight other area beaches earned ratings ranging from 85% to 98%. Water quality continues to lag at Tenean Beach in Dorchester, which scored 79% and at King’s Beach in Lynn and Swampscott, which scored just 70% in 2020.

“While we are delighted with the progress that we have made on most of the region’s public beaches, we are disappointed to report that Tenean Beach in Dorchester and King’s Beach in Lynn and Swampscott were still unsafe for swimming more than one out of every five days in 2020,” said Save the Harbor/Save the Bay’s Executive Director Chris Mancini. “We are particularly concerned about the situation at King’s Beach, where filthy, bacteria laden discharges from both Lynn and Swampscott at Stacey Brook continue to threaten public health.”

“Our kids and families deserve better. Today we are calling on the Lynn Water and Sewer Commission and the Swampscott Water and Sewer Department to work together with Save the Harbor/Save the Bay, state and federal regulators, and the community to Save King’s Beach, which is a critical recreational asset to Lynn’s kids and families. This is an environmental justice issue in a diverse, dense city where healthy green and blue spaces are at a premium,” Mancini said.

Save the Harbor/ Save the Bay is also concerned about the accuracy of the beach flagging and posting protocols, where bacteria testing triggers swimming advisories.

According to Save the Harbor’s Director of Strategy & Communications Bruce Berman, one problem is that postings are always a day late because beach managers must wait up to 36 hours to obtain test results.  Beach water quality may have already changed significantly during this period, so the prior day’s tests often do not reflect current conditions.

Moreover, in 2019, The Department of Public Health made additional changes to the beach posting and flagging protocols, which has resulted in additional days where beaches are unnecessarily posted with swimming advisories when they are in fact safe for swimming.

“While Save the Harbor recognizes the importance of protecting public health, the current system is often inaccurate and sometimes overly restrictive,” said Berman. “Over the coming months we plan to work with consultant Kelly Coughlin of Stony Brook Partners, and with the Department of Conservation and Recreation, the Massachusetts Water Resources Authority, MADEP, USEPA, and MADPH to develop new rainfall thresholds and protocols to improve flagging and posting accuracy.”

In the meantime, Save the Harbor/Save the Bay urges beach goers to rely on common sense when swimming after summer storms and to use the multi-year average safety ratings to help decide when and where it is safe to swim.