We often take the purity of our tap water for granted -- and we shouldn't. A carefully researched, documented and peer-reviewed study of the drinking water systems of 19 U.S. cities, found that pollution and deteriorating, out-of-date plumbing are sometimes delivering drinking water that might pose health risks to some residents.

Many cities around the country rely on pre-World War I-era water delivery systems and treatment technology. Aging pipes can break, leach contaminants into the water they carry and breed bacteria -- all potential prescriptions for illness. And old-fashioned water treatment -- built to filter out particles in the water and kill some parasites and bacteria -- generally fails to remove 21st-century contaminants like pesticides, industrial chemicals and arsenic.

Because coffee and tobacco are so widely used, researchers say their byproducts are good indicators of the presence of pharmaceuticals. Thus, they routinely test for, and often find, both caffeine and nicotine�s metabolite cotinine more frequently than other drugs.

Tap water can contain a vast array of contaminants, but a handful showed up repeatedly in the water of the cities we studied:

Lead, which enters drinking water supplies from the corrosion of pipes and plumbing fixtures and can cause brain damage in infants and children

Pathogens (germs) that can make people sick, especially those with weakened immune systems, the frail elderly and the very young

By-products of chlorine treatment such as trihalomethanes and haloacetic acids, which may cause cancer and reproductive problems

Arsenic, which may cause cancer, serious skin problems, birth defects and reproductive problems

Radon, the rocket fuel perchlorate and other carcinogens or otherwise toxic chemicals.

The best type of drinking water is from a natural source (mineral water). But these types of water are more expensive. City water (chlorinated) is consumable by man but in the long run, chlorine is bad in our body. You can instead install a small water purifier to clean your drinking water through a ceramic filter, carbon filter, sand filter and finally soaked with mineral rocks.

If you are concerned about the quality of the water and its pollution perhaps you might want to attach a filter to your kitchen tap to filter out all the junk. If you boil your water you will eliminate the chlorine and kill most of the bugs that may be in it.

The bottom line is this: the tap water in some cities might pose health risks to vulnerable consumers -- people who have serious immune system problems, pregnant women, parents of infants, those with chronic illnesses and the elderly should consult with their health care providers about the safety of tap water. And our nation must make a major commitment to upgrading and modernizing water systems and protection of drinking water sources.