Not necessarily so, according to Dick Harris of Earthplace in Westport, who has been monitoring water quality on the Norwalk River and its major tributaries for five years. This year, Mr. Harris' tests showed the river exceeded the Department of Environmental Protection's goals for fecal coliform and E. coli bacteria at all 10 testing sites on the Norwalk River, and Mr. Harris said the suspected cause would surprise many people. At one site, just above the town line in Ridgefield, the bacteria concentration was more than 230 times the level set by the DEP.

"Almost everything is residential, although we had one sewage treatment center that went one year. It's mostly septic tank management, mowing straight to the water's edge, too many geese, all sorts of things," said Mr. Harris, who runs the Harbor Watch River Watch program as well as a state-certified water testing lab.

The problem, however, is getting individual property owners interested and aware of the repercussions of their actions, whether it be not maintaining their septic systems with regularly scheduled cleanouts, or planting grass right down to the riverbanks.

"That is the big barrier we're all wrestling with, and we don't have the answer," said Mr. Harris.

One of the simplest things homeowners can do to make sure they aren't contributing to pollution is to maintain their septic tanks and get them pumped on a regular basis. "I don't think that people pump out their tanks enough. It's in the homeowners' best interest to maintain their septics, because boy is it an expensive fix" said Patricia Sesto, Wilton's director of environmental affairs.

Septic tank failure, at least in one location just north of the town line in Branchville, may be one of the largest contributors, according to Mr. Harris. During his testing throughout the year he found unusually high readings well above the state goal of 126 E. coli cells per 100 milliliters of water. On one particular day a drainage ditch leading into Cooper Brook, which runs into the Norwalk River by Ancona's market, had an E. coli level of 29,000.

Mr. Harris began tracking the source of the extremely high levels of bacteria, taking samples just below the drainage ditch as well as above it to make sure the bacteria weren't coming from further upstream. He said the E. coli seems to be coming from a residential area above and behind Ancona's, and he believes septic tank failure could be the problem.

"At this point we really need to get the town and some experts to nail it" said Mr. Harris. The Cooper Brook bacteria counts, however, aren't the only high level readings Mr. Harris got as he tested the water quality from the head of the river in Ridgefield down into Norwalk.

At various testing sites in Wilton, Mr. Harris's studies found E. coli concentrations fluctuating wildly, regularly rising above 200 to 300 E. coli cells per 100 milliliters, and after periods of heavy rain he recorded numbers as high as 5,800.

"It's really kind of difficult in an area like the Norwalk River to meet those goals," said Chris Malik with the DEP Bureau of Water Management.

Mr. Malik said bacteria and other pollutants build up on roadways and in parking lots and lawns surrounding the river, and when a heavy rain comes through everything gets washed into the river at one time, causing large spikes in the bacteria counts. "It's a challenge, and if we go a long period without rain then that first flush is going to be really high," said Mr. Malik.

Mr. Harris, Ms. Sesto and Mr. Malik all serve on the board of the Norwalk River Watershed Initiative, a conservation consortium working to protect and restore the Norwalk River watershed. Along with in stream restoration projects sponsored by the initiative, public education is a key priority of the group.

The fecal coliform and E. coli bacteria strains Mr. Harris found are not harmful to humans, but act as indicator species for other, more harmful bacteria.

The presence of these microbes and their frequency in the river give scientists a good estimate of what other things may be present in the water, said Mr. Harris.

According to Lee Dunbar, a supervising environmental analyst at the DEP, the fact that the Norwalk River failed to meet the state's goals shows just how rigorous they really are. "What we have right now is a criteria based on protecting bathing beaches where the state encourages people to come and swim," said Mr. Dunbar.

Swimming is not the recreational use most prevalent on the Norwalk River, but the state still sets the water quality goal at that level, he said. At bacteria levels just above the state goal, Mr. Dunbar said eight swimmers out of 1,000 who ingested water would suffer from a stomach ache.

Addressing the sources of the pollution is something the DEP is looking to do, but it relies on cooperation with residents, said Mr. Dunbar. "It's an uphill fight. A lot of it is not stuff that the state can go in and mandate. It's things that individuals and towns can do on their own," he said.

There's a good side to this story, too, said Mr. Hams, and that is the town involvement in water quality. When Mr. Harris's studies showed that a farm along the banks of the Silvermine River was contributing a large amount of animal waste directly into the river, the town acted quickly, working with the property owner to reduce the runoff, he said.

"Wilton has been very good. When we pointed out the farm, they got right on it. I have found Wilton to be very responsible," said Mr. Harris. Steven Schole, director of Wilton's health department, said working with residents to solve problems when they are found is the key to getting things done.

"We don't really coddle people, we work with them. We don't take vigorous action against them, until it is necessary”, said Mr. Schole. Mr. Schole said just blaming septic systems for water quality degradation is premature, however, and it needs to be proved before moving forward. "The bacterial indicator itself does not prove that it's human sewage from a septic system. It has got to be pinpointed," said Mr. Schole. Once a problem area is located, dye tests can be performed on a septic system to see if it is the source of the bacteria, he said.

Mr. Harris said a lack of regulatory authority in going after problem septic systems weakens the responses available to towns. "There are no laws on the books to enforce septic tank maintenance and cleanouts," said Mr. Harris. In fact, Mr. Harris said, the way the state deals with home heating oil tanks as compared to septic systems is a good comparison. Right now "oil tanks are treated like God" and if there is a problem, or a leak, the state and local agencies step in immediately to force a massive cleanup, said Mr. Harris.

There is no such action on septic systems, he said, and while oil separates from water, floating to the surface, E. coli and other bacteria mix right into the water, making it a much more pervasive danger.

A proactive approach by the state and local municipalities, and a campaign to educate people on the environmental effects of their actions, are the steps necessary to improve water quality, said Mr. Harris.

"I'm at a point where I'm not going to try to scare people. There has to be a measured response," he said.