Editor's note: This is the first in an occasional series looking at drinking water issues around the region.

It happens to even the best drinking water in the country and happens here in this area.

Like many water utilities across the U.S., disinfectants like chlorine are added to the supply to remove life-threatening microbes.

But when the disinfectants interact with organic material - anything from algae to dead leaves to animal carcasses - that seeps into drinking water, new chemicals are formed that could be a potential health hazard.

It is a delicate balance for those who oversee municipal water supplies, said Glens Falls City Engineer Steve Gurzler.

"You have to minimize the organics in distribution and minimize the chlorine while keeping enough residuals to protect public health," Gurzler said.

Chemicals created by organics mixing with disinfecting agents are among the most common found in the area's tap water, according to the Environmental Working Group, a Washington, D.C.-based conservation advocacy group that compiled a database of chemicals found in nearly every municipal water supply in the United States.

The group, which spent the last three years compiling the information now has it posted on its Web site, ewg.org.

The group found more than 300 different pollutants in tap water consumed by Americans every day.

"The federal government has really dropped the ball on drinking water standards," said Olga Naidenko, a senior scientist with the group and one of the authors of its drinking water report. "The last (regulation) was set in 2001 and the EPA Office of Water did not decide to regulate any new contaminates. We are alarmed because these pollutants are out there and we don't seem to have a plan on the national level on how to deal with them."

The common denominator for tap water in Warren, Washington and Saratoga counties - including municipal tap water in Hudson Falls, Fort Edward, Queensbury, Whitehall and Glens Falls - appears to be high levels of chemicals like chloroform, bromodichloromethane and dichloroacetic acid.

All of these are formed when chlorine is added to the drinking water to kill microbes and bacteria.

In Glens Falls, for instance, the water system has tested positive for above-average levels of those chemicals since 2004.

The health limit, 5 parts per billion, has been exceeded multiple times over the last five years. The average test has found the level of chloroform, for example, to be at 27.49 parts per billion.

The caveat for some of the information found the site, according to the state Department of Health, is that the group posted in some instances test results of treated and untreated water.

For example, high levels of TCE, or trichloroethylene, was found in some untreated drinking water for the village of Fort Edward.

Jeffrey Hammond, a spokesman with the Department of Health, said the blended test results produced the high levels. When the Environmental Working Group was notified of the discrepancy, the high TCE levels were corrected and removed from the site.

But prolonged levels of the disinfectant byproducts can be troublesome.

"The big concern like chloroform and chemical type products have been associated with cancers," Naidenko said. "We are in fact quite concerned about them. However, most places people have tap water that does have them."

Can't stop treating

Gurzler, the Glens Falls city engineer, said the bigger danger is letting the microbes and bacteria through.

"The health benefits from chlorination are huge," he said. "When you compare the risks of disinfection and disinfection byproducts, it's kind of a no-brainer to keep this thing."

Waterborne illnesses like cholera and typhoid - common killers a century ago - have become far more rare in U.S. drinking water thanks to chlorination.

Part of the trouble for Glens Falls' water comes from the Halfway Brook reservoir on West Mountain. It is a large, but relatively shallow reservoir where organic material like algae has been found.

"We get more algae growth because it's shallow and has more nutrients coming into it," Gurzler said.

He added that the city keeps frequent tabs on the water quality. Nearly 2,000 water quality tests have been performed on Glens Falls water since 2004, which is 1,600 more than the national average for tap water monitoring.

The city also recently completed a federally mandated intensive sample program for byproducts.

"We do have a very good filtration system," he said. "As far as regulations go, we are currently in compliance until the year 2013 for our filter process."

When it comes to monitoring for these byproducts, the government has done a pretty good job, said David Carpenter, a professor of environmental science at the University at Albany.

"It's not a trivial issue, but they are regulated quite well," Carpenter said.

He also agreed with Gurzler that the bigger risk is posed by infectious organisms that the chlorine wipes out effectively.

But high levels of the byproducts being found is a sign that a better filtration system is needed, Carpenter said.

The problem of disinfectants mixing with organic material is one nearly all water utilities across the country must face, said Lynn Thorpe, a senior policy analyst at Clean Water Action in Washington.

Thorpe's group has lobbied for stronger clean water regulations and investments in infrastructure.

"There's been a lot of activity over the last 20 years to crack down on these disinfection byproducts," Thorpe said. "Instead of using straight chlorine, they use chloramines."

Utilities like Glens Falls have worked hard to control organic matter entering the water supply.

But a system is needed on the federal level to control agriculture runoff and protect drinking water sources, Thorpe said.

"We don't have a really good system for agriculture runoff and control. It's pretty much all over the country," she said. "We have a lot of organic matter in our water due to human and agriculture activity. With all our fairly complicated drinking water regulations, there's no federal mandate for source drinking water."