SouthCoast beaches are the cleanest in the state this year, according to a new report from the Environment Massachusetts Research and Policy Center.

The center's 2021 Safe for Swimming report shows the results of testing 556 beaches in the state for fecal bacteria like E. coli.

It revealed Bristol County has the lowest average percentage of days with potentially unsafe water of all eight seaside Massachusetts counties.

Bristol County beaches were deemed potentially unsafe just 2% of the time on average, according to the center's data.

This represents half the average of the next-best Dukes County, covering Martha's Vineyard and the Elizabeth Islands.

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Meanwhile, at the top of the list, Norfolk County beaches were deemed potentially unsafe an average of 12% of the time.

“We’ve come a long way in cleaning up bacteria pollution from sewage and stormwater runoff all across Buzzards Bay," noted Mark Rasmussen, president of the Buzzards Bay Coalition, which works to restore clean water in the area.

Rasmussen went on to state that millions of dollars in sewage infrastructure upgrades in New Bedford have dramatically improved the water quality and given residents "great, clean beaches."

"We still have a lot of work ahead to clean up other forms of pollution to our waters, particularly nitrogen, but this report should be celebrated for the milestone it represents," he added. "When our communities invest in clean water, the Bay bounces back, and all of us get to enjoy the benefits.”

Getting deeper into the data, Bristol County had twice as many beaches tested as Norfolk County (44 beaches compared to 22), although the study notes that not all beaches were tested at the same frequency and that county-to-county data may therefore not be directly comparable.

Plymouth County — which has beaches on both the SouthCoast and the South Shore — was deemed potentially unsafe for swimming an average of 6% of the time, with 83 beaches tested.

No Plymouth or Bristol County beaches were listed in the ten Massachusetts beaches deemed the least safe for swimming.

The worst offender, King's Beach in Essex County, had potentially unsafe levels of bacteria 64 days out of 85 days tested, or 75% of the time — more than twice the number of unsafe days as the next worst beach, Suffolk County's Tenean Beach.

But King's Beach is also the only beach in the list with more than one testing site, which the study authors note could skew the results.

It's Not Just Bacteria...Here Are Some Other Harsh Realities About New England Beaches

Everyone loves a day at the beach and on the SouthCoast, the waterfront is everywhere. But the sand and sun people usually picture in their heads is not always the reality in New England.

Tired of Massachusetts Beaches? LOOK: See America's 50 Best Beach Towns

Every beach town has its share of pluses and minuses, which got us thinking about what makes a beach town the best one to live in. To find out, Stacker consulted data from WalletHub, released June 17, 2020, that compares U.S. beach towns. Ratings are based on six categories: affordability, weather, safety, economy, education and health, and quality of life. The cities ranged in population from 10,000 to 150,000, but they had to have at least one local beach listed on TripAdvisor. Read the full methodology here. From those rankings, we selected the top 50. Readers who live in California and Florida will be unsurprised to learn that many of towns featured here are in one of those two states.

Keep reading to see if your favorite beach town made the cut.