•FACT: Millions of private and public wells have never been tested for contaminants, but a five-year, $12 million, nationwide survey was conducted by the EPA and released in 1990. Based on that survey, the EPA estimates that 10.4 % of community wells and 4.2 % of rural domestic
wells have detectable levels of at least one pesticide.

•FACT: The U.S. Geological Survey has pinpointed sources of contamination in every state.

•FACT: Every bottled water isn't necessarily without contamination. Some bottled water isn't regularly monitored. In 1990, a bottled water survey by the Suffolk County, New York, health department tested bottled water sold in the county and found that 9 of 88 brands tested did not meet state and federal drinking water standards.

•FACT: Approximately 75 % of U.S. households have chlorinated water. In 1987 a study sponsored by the National Cancer Institute, the Food and Drug Administration, and the EPA found increased risk of bladder cancer with long-term consumption of chlorinated drinking water. This is
believed to be associated with the formation of disinfection byproducts in water from chlorine, such as THMs.

•FACT: According to EPA estimates, 40 million Americans are exposed to levels of lead in water well above the EPA's proposed maximum contaminant allowances.

•FACT: Virtually everyone has some level of radon in their water. The national average is 200 to 600 picocuries per liter. At these levels, scientists estimate the risk of developing cancer from radon ingestion is greater than the risk of cancer from most other regulated contaminants found in drinking water at the maximum levels allowed by the EPA!

•FACT: Giardia lamblia cysts have become the most common cause of waterborne disease in the United States. Although reporting is voluntary, more than 23,000 cases of Giardia lamblia caused disease were reported between 1960 and 1980. It also appears that the rate of outbreaks is increasing.

•FACT: Major outbreaks of disease caused by Cryptosporidium oocysts were reported in Texas in 1985, in Georgia in 1987, England in 1989 and Wisconsin in 1994. A limited sampling of western U.S. waters found Cryptosporidium oocysts in 28 % of treated drinking water samples evaluated. A study of eastern U.S. waters showed these oocysts present in 11 of 28 of the treated
water samples.
 

"Assuring safe drinking water will not be cheap. As public water systems build new treatment facilities to meet more-stringent standards, most families will find their water bills rising. Meeting expected federal requirements will cost the nation's water suppliers more than $18 billion, the EPA estimates. Ultimately, the only sure way to guarantee safe water is to protect the source. But only a handful of communities nationwide have tough ordinances protecting their water supplies. Dade
County, Fla., for instance, now prevents new businesses that use hazardous materials, like dry-cleaners and auto repair shops, from locating right over water-well fields. Several towns northwest of Boston are planning similar zoning laws. These communities acted only after they had poisoned vital wells. One can only hope that other American communities will recognize the value of their drinking-water before their wells and reservoirs go bad.

Health Effects of Selected Drinking Water Contaminants