"Even an advanced country like the United States is facing significant water problems relating to availability, purity, and quality. Over 700 chemicals have been detected in U.S. drinking water as it comes out of the tap. EPA has classified 129 of them as being particularly dangerous. Drinking bottled water does not assure the absence of contaminants. The sad fact is that pollution of drinking water is a problem for about half of the world’s population." (Quoted from article)