The New York Times today ran a troubling story about the nation's drinking water supply, reporting that as many as 19 million Americans get sick from drinking tap water from regulated water systems each year.

It reports that more than 20% of the 54,700 U.S. water treatment systems have reported illegal levels of chemicals, radioactive substances or bacteria in the past five years, yet of these only 6% were ever punished.

An EPA representative is being questioned by the Senate Environment and Public Works committee today about the agency's enforcement of the Safe Drinking Water Act, first passed in 1974 and most recently amended in 1996.

The act regulates all water systems supplying more than 24 people and sets maximum limits for naturally occurring and man-made substances, including chemicals and bacteria.

To envision the maximum levels of contaminants, which the EPA expresses in parts per million, imagine a bathtub full of particles the size of grains of salt. About a billion would fill the tub. If this tub was tap water, no more than 10 of these grains could be arsenic. Fewer than five grains could be tricholoethylene, a degreaser. Two grains of vinyl chloride, leaching from PVC pipe, would reach the legal limit. The water also must be 99.99% free of cryptospridium, giardia lambia and other active viruses.

How can you tell if your water supply is safe? Each provider is required by law to prepare and distribute an annual report about its water, and should provide it to you upon request. Mine comes in our water bill and is also online.

From it, I've learned that in the past year my system has detected coliform bacteria, lead, copper and assorted chemicals, but in allowable concentrations. There do not appear to have been any incidents of water contaminated beyond EPA-regulated limits. Yeah!

Americans drink about a billion glasses of tap water a day, and use on average 100 gallons per person per day, at a cost of $.002 per gallon. Few of us think to mention water when we list the blessings we enjoy, but just lose it for a day and we'd remember how fundamentally important it is to our well being.