At first glance, Kennebunkport’s Goose Rocks Beach looks as perfect as a postcard. Gentle waves lap peacefully along three miles of fine silver-white sand. At one of southern Maine’s most secluded stretch of beach, the tastefully chic houses continue to rent upwards of $5,000 a week during this summer’s peak season. No amusement parks or T-shirt shops mar the quiet charm here — goodness, it was only last year that this highly private community agreed to accommodate occasional day trippers by permitting installation of two Porta-Potties.

But something’s wrong with this picture. Under a microscope, the bacteria in the beach water flourishes with abandon, frequently at levels 100 times acceptable federal standards. “Goose Rocks looks like that perfect little family that no one would imagine has a problem behind closed doors,” says Judy Barrett, Kennebunkport’s public health nurse. “The beach looks so pretty, so pristine — so people assume there’s not a problem.”

When visitors stop to smell the salt air on Goose Rocks, state health officials hope they’ll notice the “SWIM AT YOUR OWN RISK” signs prominently posted at 13 beach entrances. Also new this year is the town of Kennebunkport’s website warning — when the bacterial count tallies particularly high, officials now politely recommend that “water contact be avoided.”

Last summer, when the bad-bacteria news first hit, the town appropriately responded with utter shock and disbelief. “People were worried about this problem reducing the value of their property, not the health of their children,” says Barrett. “My job, however, is to be concerned with public health — I worry about the toddlers sitting in tidal pools, the elderly woman with diabetes, the person with H.I.V. or any other cause of fragile health — these people simply should not even have their feet in water testing 10 times the acceptable level of fecal bacteria.”

In fact, before last summer, this beach water had never been tested. When Kennebunkport first volunteered to participate in the Maine Healthy Beaches Program — a partnership between the Maine State Planning Office, University of Maine Cooperative Extension and the Maine Departments of Health and Human Services, Environmental Protection and Marine Resources — no one believed in the potential of such pollution. After all, in 1993, a sewer system was installed, so it’s been over a decade since raw sewage was directly dumped into the water off Goose Rocks Beach. Kennebunkport was appalled when last year’s testing warranted that advisories against swimming be posted for 28 days. This year, Healthy Maine Beaches believes the signs will stay up through early fall.

Economically, this bad news continues to affect Kennebunkport’s tourism business — beach season lasts 10 to 12 weeks at best. Cranky vacation renters request rebates, inspiring homeowners to demand tax refunds. According to Dick Leeman, president of the Kennebunkport Chamber of Commerce, Kennebunkport’s primary market is out-of-state visitors, primarily from Boston. “And all our research indicates that these people are coming for the beach,” sighs Leeman.

While the federal standard for swimming is 104 colonies of Enterococci bacteria per 100 milliliters of water, the scientific community’s standards are even stricter. Enterococci, an indicator of fecal matter, carry bacteria, parasites and viruses that most assuredly make bathers ill. According to Dr. Stephen Jones, research associate at the University of New Hampshire, 35 colonies per 100 ml is an acceptable risk and at this ratio eight out of 1,000 bathers will suffer gastro-intestinal disease.

On Goose Rocks Beach, however, the issue of federal-versus-scientific standards on acceptable risk levels of Enterococci in beach water is remote, if not esoteric. Here, the bacterial count frequently runs from 700 to 1,000 colonies per 100 ml — seven to 10 times the acceptable federal standard. When the news first hit Kennebunkport last summer, water testing zoomed from once a week to daily and the U.S. Environmental Protection Agency (EPA) and the Coast Guard were called in; the Maine Geological Survey analyzed the tides and currents in the area and concluded the problem was coming from the land, not the sea. Goose Rocks Beach is situated between the Batson and Little Rivers, and theories for high bacteria counts have ranged from unusually high tides washing waste from salt marshes into the ocean, to an increase in dogs, horses and other domestic animals on beaches. Potential human sources include leaking septic tanks or sewer pipes.

On Goose Rocks, new development meets old septic systems on watershed property – a veritable recipe for “nonsource” tough-to-identify pollution, according to John Glowa, environmental specialist for the Maine Department of Environmental Protection. “Ultimately, all this research may show that the problem can’t be solved,” worries Glowa. “We might not identify enough sources and remove them to make acceptable water quality.”

Is all this Enterococci animal or human? That’s the question that currently plagues Kennebunkport. In the hope of pinpointing the cause of their non-source pollution, the town decided to spend $27,000 for an environmental assessment from Forrest Bell, owner of FB Environmental. In the month of August, Bell and his team will hit their canoes, hunting for hot spots and taking at least 250 water samples primarily in areas that drain down to the beach. By using a fluorometer, Bell will analyze Goose Rocks’s beach water with ultraviolet light. “High fecal plus high optical brighteners will determine faulty septic systems or leaky sewer pipes,” explains Bell. “On the other hand, if we find high fecal matter, low optical brighteners, it’s likely the cause of the problem is the warm-blooded animals living upriver.”

“A lot of people are working very hard on this problem,” asserts Esperanza Stancioff, program coordinator of the Maine Healthy Beaches Program at the University of Maine Cooperative Extension/Sea Grant Department. “This problem didn’t happen overnight and it isn’t going to be solved overnight — anytime there’s development on a wetland, you run a risk.”