TESTS ASIDE, MOST WATER IS ACCEPTABLE

Water is essential to life, and an adequate supply of pure drinking water is a big topic these days. Sales of pricey bottled water are booming as thirsty Americans seek to quench both their thirst and their desire to drink something they consider healthy and tasty.

But there are alarms sounding throughout the land regarding safe water. Most recently, the Centers for Disease Control has found that private wells in Missouri have the worst contamination among nine states surveyed. These were states affected by the 1993 flooding. The CDC survey found well water contaminated with bacteria from human and animal waste. So far, there is no conclusive link between the germs and the flooding.

Across the Mississippi River in Illinois, a study by the Environmental Working Group and Physicians for Social Responsibility cites a link between farm chemicals in municipal water supplies and the risk of cancer. Farm groups, however, question both the study's findings and the standards used by the study. Agriculture groups stress that farmers have significantly reduced the use of chemicals -- some 27 percent from 1978 to 1985, for example.

What neither of the studies in Missouri and Illinois make clear is whether or not there is a real health danger. Most acceptable water supplies have some things in them that aren't desirable, but the level of pollutants is below generally accepted safety levels. That has become an issue, because studies continue to be conducted showing germs and chemicals in water without establishing the real risk to humans.

In one study, for example, scientists confirmed the presence of risky chemicals in water supplies but quickly added that a human would have to drink hundreds of gallons of the tainted water a day to incur any real risk. This finding is reminiscent of warnings and outright food bans from the federal Food and Drug Administration regarding artificial sweeteners and food dyes a few years ago. Does anyone remember how many boxcars of cyclamates you would have to eat each day to incur a cancer risk?

Watching out for safety in our food and water is no joke, however. Prudence is the best course if there is doubt about what is in the drinking water. People with private wells can have their water tested by private and government laboratories. Municipal water supplies are constantly monitored for safety. All in all, Americans can drink water from approved sources with some degree of confidence that they aren't endangering their health.

And for those who choose bottled water, here is a thought: Much of the water in designer bottles with fancy prices comes from the same source as the water that comes through your kitchen faucet. In some cases it has been filtered to remove some unwanted flavors, and in other instances special flavorings have been added. Interestingly, a taste test by the St. Louis Post-Dispatch, reported over the weekend, rated one of the bottled waters dead last -- right below common tap water.