Even though the United States is home to more than 50,000 water utilities and these systems are considered some of the safest in the world, the Centers for Disease Control consistently record disease outbreaks from various sources of drinking water.
Contamination occurs from such sources as sewage releases, naturally occurring chemicals and minerals such as arsenic and uranium, fertilizers, pesticides, manufacturing, and malfunctions in wastewater treatment systems, according to the CDC. Contaminated water can lead to health issues such as gastrointestinal illness, reproductive problems, and neurological disorders. Especially vulnerable are the elderly, infants, pregnant women, and individuals whose immune systems are compromised.
Scientists are trying to learn more about the disease-carrying organisms that live in the millions of miles of mainly underground pipes across the country. They know that the quality of the water that is sent out from treatment systems is higher than the quality of water that reaches the faucets in our homes.
Although most water is treated either with chlorine or ultraviolet light, researchers are working to find additional or better treatment methods. Chlorine treatments kill such diseases as typhoid, cholera and dysentery, but many millions of organisms survive. Some simply are not being killed, while it appears others are becoming resistant.
Water supply utilities, whether public or private, are required to provide an annual report to customers, called a Consumer Confidence Report. In this report you will find information on the quality of the drinking water in your community, the source of the water, any contaminants found there, and how you can get involved in protecting your drinking water. We recommend you check it out.
http://www.cdc.gov/healthywater/drinking/public/understanding_ccr.html
http://water.epa.gov/drink/local/index.cfm