On Sunday, 23-year-old Kenny Heisler and friend Michael Brown, 23, both of Holyoke, Mass., drove 90 minutes to get to Rocky Neck State Park in East Lyme, paid the $22 out-of-state fee and joined many others on the beach who were sitting looking out at the water after just going in it.

“We just got back,” Heisler said.

But when they were informed that the nonprofit environmental organization Save the Sound recently gave the beach a D+ grade for having high amounts of bacteria last year, they said it might not have stopped them from going in.

Each year, Save the Sound releases letter grades for Rocky Neck and all other beaches along Long Island Sound based on bacteria samples collected by local health departments. The grades always reflect the previous year. Grades released in 2024 reflect samples taken in 2023.

In the 2024 grades, Rocky Neck beach scored the lowest in southeastern Connecticut, while Eastern Point Beach in Groton and several others in the region got A+ grades.

Save the Sound Director of Water Quality Peter Linderoth said that doesn’t mean Rocky Neck isn’t a “really great beach,” but “it does have this occurrence, over (the last) five years ― this bad grade.”

“When concentrations of bacteria are high, the waters are more risky for people to swim in ― in relation to getting sick,” he added.

The bacteria samples are collected in waist-deep water, transported to a state lab and tested for concentrations of Enterococci, a bacteria commonly found in the intestinal tracts of warmblooded animals, Linderoth said. The sources of the bacteria vary widely, from feces of warmblooded animals to storm water runoff, and can indicate many different pathogens in the water.

“When you look at Rocky Neck, it’s surrounded by wooded areas and marsh,” Linderoth said, adding those conditions would be right for fecal contamination from animals.

Heisler joined over 100 others Sunday who went in the water in the afternoon. He said if there had been a sign at the entrance to the beach that said something along the lines of: “Hey, you might want to rethink going in the water,” he would likely have avoided swimming there.

There is a warning sign at an entrance to the beach that reads: “No swimming in this area due to potentially high bacteria levels, unsafe currents and rocks.”

Montville resident Nicole Funk, 25, recalled that the beach had shut down for a little while last year.

“I think if the water temperature was good, I would still go in,” Funk said after learning about Rocky Neck’s D-plus rating, with friends agreeing.

“We’re going to go in the water soon,” said Middletown residents Tilla Ruser and Walther Mothes, who were also taking their first beach trip of the season at Rocky Neck.

“This is a nice beach,” Mothes said. “It has really good waves.”

The two arrived around 11:30 a.m. and sat in shaded beach chairs. Ruser said she had checked the water quality on a website before they arrived, and had seen the quality was good.

“We do follow the reports,” Mothes said. “But it’s still early in the year.”

Mothes, a microbiologist, explained that the bacteria level increases along with the temperature of the water.

“If you look at the shutdowns, it’s late in the year,” he added.

Meanwhile at A+-rated Eastern Point Beach in Groton, there were fewer beachgoers Sunday.

Waterford resident Diane Pezzolesi, who sat with Groton resident Karen Anight, said the water looked clean.

“We love to swim, so the fact that we can go out and it’s pretty clean is nice,” she said of the water.

A little farther down the beach, Groton resident Tammy Panciera said the water there was “absolutely clean.”

”I grew up in Rhode Island and I’ll take this over Misquamicut any day,“ she added.

Panciera said if Eastern Point had gotten a D+ grade, she would not going in the water, and would discourage others from doing the same.

Save the Sound is looking at the grades at Rocky Neck and working with a University of Connecticut professor to perform DNA sampling in hopes of finding the source of the bacteria there.

“What gut it came out of,” he said. “Or guts. It could be plural ― and I think with Rocky Neck area, we’re going to find that a good percentage of that bacteria present in the samples might be from water fowl. That’s not as dangerous as human sewage. But it still needs to be looked at.”

d.drainville@theday.com