enlarge Gregoy Rec/Staff Photographer

Sean Radel, 7, swims at Gooch’s Beach in Kennebunk on Tuesday. Gooch’s had pollution advisories this summer, but it has improved.

KENNEBUNK —  When Tina Radel moved from the New Jersey shore to Kennebunk three years ago, the last thing she expected was having to keep her children out of polluted beach water.

"Coming from there to here, you think it's going to be pristine," she said.

Gooch's Beach isn't quite pristine, and heavy rains caused a few pollution advisories here this summer. But Gooch's is one of several Maine beaches that are less polluted today thanks to a six-year-old statewide monitoring program and state and local cleanup efforts.

"It's significantly improved," said Keri Lindberg, coordinator of the Maine Healthy Beaches program.

At the same time, the expanding testing program continues to reveal contamination in new places, especially after heavy rain like Maine experienced in June and July. High bacteria counts turned up in Old Orchard Beach and York Harbor this summer, Lindberg said.

"This has been the most challenging year for water quality that we've ever had," she said.

A decade ago, no one was testing water quality at the vast majority of Maine beaches, or warning swimmers that heavy rain was flushing bacteria and other potentially harmful pollution into the surf.

New Jersey, for example, had been testing beach water since the 1980s, but it was widely assumed that the ocean was clean along Maine's shore.

Today, 60 Maine beach areas are tested, most of them on a weekly basis, and the results are posted at the beaches and online at mainehealthybeaches.org.

A test that shows 104 Enterococci bacteria per 100 milliliters of sample water could lead to an advisory against contact with the water, although the decision about whether to post a warning also is based on the history of the area and the time of the last rainfall. Swimming in contaminated water can cause diarrhea, vomiting or sinus infections, as well as skin, ear, respiratory, eye and wound infections.

After six years of testing, it's clear that Maine's water can be pretty dirty, depending on how much rain falls during beach season.

"This program is really helping communities find out if there are problems," Lindberg said. "Generally, water quality is very good in Maine, but it's a good rule of thumb to stay out of the water during and after rainfall. ... It's not the rain itself, it's what the rain is carrying."

Gooch's experienced a rash of high bacteria counts from 2005 to 2007 because of pollutants being flushed into the water by rainstorms. The potential culprits ranged from duck excrement to boat discharges to malfunctioning septic tanks along the Kennebunk River, which empties into the ocean just north of the beach.

Officials with Maine Healthy Beaches and the Maine Department of Environmental Protection will be back on the river Thursday as part of an ongoing study to determine whether the bacteria washing downriver is coming from human waste or animal waste, then find the sources.

The high bacteria counts prompted efforts to divert stormwater and educate residents about maintaining septic systems.

"We're doing all we can," said Brian Costello, Kennebunk's parks and recreation director and beach manager.

The work is credited with cleaning up the water and reducing the need to post advisories in the past two years.

Radel has noticed the improvement, she said, and she took her children to Gooch's on Tuesday with no reservations about the water.

Her children clearly weren't worried, as they dug in the sand and played in the waves. Asked whether the water seemed clean, 7-year-old Sean Radel was unequivocal. "Yeah, no seaweed," he said.

Maine Healthy Beaches is federally funded and is part of a nationwide effort to clean up beach water.

An annual review of water quality released last week by the Natural Resources Defense Council showed some progress nationwide. It also...