The Connection Between Tap Water and Cancer

Many health experts and diet / fitness consultants advise people to drink plenty of water each day, but there is a potential dark side to drinking too much tap water.

Over the past few decades, there have been several studies linking tap water contaminants to various cancers. Even more frightening is the fact that some of the most dangerous contaminants in tap water are actually byproducts of water purification.

Municipal Water Purification and Carcinogens

Many municipalities use chlorine to kill bacteria and other microorganisms in drinking water. When this chlorine combines with certain organic materials, including leaves, sewage, manure and others, chemical reactions occur. These reactions release various carcinogens into drinking water.

A 2011 study by the Environmental Working Group, a noted environmental organization, looked at contamination in large municipal water systems in 43 states. Combined, these systems serve over 100 million people. The study found that trihalomethanes, which are byproducts of chlorination, were present in all surveyed municipal water systems. Many of these compounds are on the EPA's list of probable human carcinogens.

While the EPA regulates levels of some of the toxins produced by chlorination, many others are not regulated. In addition, some watchdog groups, including the Environmental Working Group, argue that the allowable levels of regulated chlorination byproducts are too high.

Exposure to Chlorine Byproducts and Cancer

Individuals are exposed to chlorine byproducts when they use tap water for drinking, bathing, swimming and washing. These byproducts cause cancer by increasing free radicals in the body. Free radicals make cells more vulnerable to the mutations that lead to tumor formation.

Specific Cancers Linked to Chlorination

A link between exposure to chlorine byproducts and many types of cancer, including certain types of leukemia, breast cancer and others, has been proposed. Two of the cancers most strongly linked to chlorinated tap water are bladder and colon cancer.

Bladder Cancer

Several studies, including a 2007 study published in the American Journal of Epidemiology, link bladder cancer to exposure to trihalomethanes in tap water. The 2007 study shows that drinking chlorinated tap water produces a twofold increase in the risk of developing bladder cancer.

Colon Cancer

A study published in the American Journal of Epidemiology in 1997 links exposure to chlorination byproducts in tap water with an increased risk of colon cancer. In addition, a 2000 study from Cancer Epidemiology Biomarkers and Prevention, a prominent academic journal, shows a link between long-term exposure to chlorinated water and colon cancer in older men.

In addition to chlorine byproducts, tap water often contains other carcinogens. The list of potential carcinogens found in tap water is a long one, but some particularly dangerous water contaminants include the following:
•    Lead
•    Arsenic
•    Benzene
•    Benzidine
•    Cadmium
•    Chromium
•    Dichloromethane
•    Bis (2-Ethylhexyl) Phthalate
•    3,3-Dichlorobenzidine
•    Bis (2-Chloromethyl) Ether

Protecting Your Family

After reading about the link between tap water and cancer, many people turn to bottled water. This may not, however, be the best solution. Many bottled water manufacturers get their water from municipal sources, so it contains many of the same contaminants as tap water.

This is why water filtration may be the better solution. High-quality home water filters remove chlorine and many other chemicals from tap water. 

To help you choose the right filter for your family, you should obtain a copy of your local water analysis results from your municipal water provider. Providers are required to furnish this information to consumers. By looking at your water analysis results, you can identify possible carcinogens in your water supply and choose a water filter that can remove them.