With one notable exception, Dorchester’s three beaches fared well in the first yearly “Water Quality Report Card” released last month to assess and compare beach conditions around the region.

Save the Harbor/Save the Bay, an environmental advocacy group, announced the results, ranking public beaches from Nahant to Nantasket at a meeting on May 30 at the Exchange Conference Center on Boston’s Fish Pier.

Savin Hill and Malibu Beaches measured up to clean beach standards, but Tenean Beach has repeatedly been counted as one of two polluted beaches in the region, failing more than 20 percent of the tests taken this year.

Bruce Berman, director of strategy, communications and programs for Save the Harbor/Save the Bay, says that each location has to be considered individually to make sure all area beaches are safe for swimming throughout the year.

“We’re interested in building a consensus around how to solve the problem,” Berman says on going forward. “The next question is why and what we can do, and that’s really important.”

The testing done was based on a standard 100 milliliters and the percentage of Enterococcus bacteria, an indicator of fecal contamination, found in the sample to exceed a metric of “beach safety.” The three Dorchester beaches were tested daily, resulting in 73 samples taken at each location. Percentages based on overall beach safety placed Malibu Beach and Savin Hill at 91.7 percent and put Tenean on the lower end at 79.5 percent.

While the data is used to rate the general health of the beach, the report notes that flagging the beaches based on yesterday’s tests is of little help, as bacteria counts can spike from one day to the next. Beaches flagged blue or red to denote the risk of swimming are based on this often inaccurate count.

“Posting yesterday’s test results on the beach is simply not a sensible way to let the pubic know if it is safe to swim today,” said Berman. “Most of our beaches deserve a fairly high grade, but I would flunk the flags.”

The report suggests that a measurement of recent rainfall would serve as a more accurate predictor of elevated bacteria in real time. Berman says that assessing the ocean water quality will allow the group to plan the next steps to be taken in the coming months.

“Doing the report isn’t the end, it’s the beginning,” he said.

Since the implementation of the Boston Harbor Project, the water quality of Boston Harbor has improved dramatically since the completion Deer Island sewage treatment plant and the Mass Bay outfall pipe were completed in 2001. While there has been a dramatic drop in bacteria concentrations and clarity has improved, local beaches are still plagued by contaminated storm water runoff.

“The harbor project cleaned up the harbor and the bay, but it wasn’t designed to solve all of the beaches problems,” said Berman.

Berman blames storm water from outfall pipes near the beach and along the nearby Neponset River for the poor quality at Tenean. He says that finding a way to improve the quality of storm water before it hits the shore would improve the situation at Tenean.

Closing off the pipes that spewed sewage and collected rainwater has been the key to success along South Boston’s now popular beaches. Berman says that same “beach by beach” approach is exactly what Tenean needs.

Located of off Morrissey Boulevard, Tenean is small and often empty. A well-outfitted playground makes it an ideal place to bring children, but few people enter the murky water, even on warm weather days. The lack of a lifeguard on duty also makes swimming here less than ideal.

Berman describes it as “a neighborhood beach.”

“It’s not a destination beach,” says Berman. “And it’s had some water quality problems for a while. People are not in the habit of going over there to swim.”

On a warm and sunny afternoon, Dao Ha and her daughter were two of three visitors playing in the sand. She says that they come to Tenean often because of the park but they never go in the water. They travel to the better-rated beaches like Nantasket to swim.

“I’ve always lived in Dorchester and never swam out here because the water has always been dirty,” Ha said. “You can almost smell the difference from a clean beach.”

The only other sun-bather, who preferred not to be named as she was supposed to be at work, said she has frequented the beach for years and has never ventured near the water. Last summer, she said, she observed syringes dumped on the sand.

The beachgoer said she notices that the sand itself is well maintained, but where the water touches the shore is an accumulation of slime and sludge.

“They should really keep it clean because it’s a little gem,” she said.

State Senator Jack Hart, who has led annual clean-ups at local beaches focused on the surrounding sand and plantings, says that Tenean’s lingering water pollution is troubling. He wants the Massachusetts Water Resources Authority to do an assessment to determine the cause and fix it.

“It’s not sewage necessarily, but run-off from storm water during rain events. There may be illegal hookups that are contributing to the problem there,” Hart said. “I want the MWRA to have an analysis done particularly at Tenean to assess where the actual problem is and then get it to a similar level as the other beaches.”

Sen. Hart’s office will host a clean-up at Tenean Beach on Monday, July 2 from 6-7:30 p.m.