Many minerals and chemicals are used for "purification," including chlorine, alum or sodium aluminum salts, soda, ash, phosphates, calcium hydroxide, and activated carbon. Yet this process may not clear all of the many environmental pollutants that can fertilizers, and insecticides; chemicals and wastes from industry; and air pollutants such as lead or radon. Toxic organic chemicals and petroleum spills can also pollute large amounts of water. Since much of this pollution affects groundwater as well as surface waters, most municipal or artesian well drinking waters are at risk and deserve our concern.

The January 1990 Consumer Reports analysis suggests that the three drinking water pollutants of most concern are lead, radon, and nitrates.

Lead may contaminate the water of more than 40 million Americans. It occurs mainly from corrosion of water pipes, from lead solder in plumbing, and from lead in brass faucets. The possibility of contamination is of greatest concern to people living in homes more than 30 years old whose pipes contain more lead, and for families with young children, who are more sensitive to lead toxicity. Testing for lead is relatively easy and inexpensive. Reverse osmosis will remove lead; solid carbon filters may also remove it to some degree.

Radon is a radioactive gas by-product of uranium and is found in the earth’s crust. High radon gas levels are associated with an increased risk of lung cancer. This carcinogenic element can be present in any home in levels high enough to cause concern but is more likely to be found in the northeast United States, North Carolina, and Arizona. Water that comes from wells and groundwater have a higher incidence of contamination. Municipal waters that come from lakes, rivers, and reservoirs are usually low in radon. When present in the water, radon can be released into the air with showering, laundering, and dishwashing. Radon in the air at home can be tested with several new devices available on the market. If present in the water in high amounts, radon can be removed with carbon filtration, but this system must be attached to the entire water system of the home.

Nitrates are suggested to be the third main risk in water. They are present mostly in groundwater sources that have agricultural contamination; these waters may also then have higher amounts of toxic pesticides and herbicides. High nitrate levels are of greatest risk to infants and seriously ill people. Nitrates are converted to nitrites by certain intestinal bacteria; these nitrites may alter the hemoglobin molecule, converting it to methemoglobin, which cannot carry oxygen. Rural families, especially those with infants and pregnant women, should test their water for nitrates. If it is present in high amounts, either reverse osmosis or distillation systems will help to clear the nitrate molecules.

Other major concerns in drinking water are the chemicals that are released into our waters by industry and the agricultural chemical pesticides, herbicides, and fertilizers that run off into local waters. These organic chemicals are more toxic and carcinogenic at lower levels than many other contaminants. The trihalomethanes (THMs) formed in chlorinated water are also a carcinogenic concern.

However, with all these possible health threats, the government would like us to believe that we should have no concerns about our drinking water. Clearly, tap water consumption usually does not cause immediate or significant health problems unless it is contaminated with infectious organisms. Millions of people drink water from this source every day, though many avoid drinking it straight because of the taste. However, more research studying the relationship of drinking water to chronic disease needs to be done. Until we know more about tap water (and even well water) and its long-range effects, it is better to be careful and not drink it. In some areas, chemical contamination from using tap water for cooking and bathing may even be a concern. It may be worthwhile to analyze questionable water for toxic chemicals and metals, as well as analyzing its mineral content, hardness, and pH. Several companies in the United States analyze water, including Water Test in New Hampshire, National Testing Labs in Ohio, and Suburban Water Testing Labs in Pennsylvania. They all have toll free 800-numbers.