Well the simple answer is that water quality is not getting any better. According to the Water Quality Association, water is an extremely solvent substance that is easily contaminated by everything it touches. In more than a third of the United States, mineral deposits create "hard water" that may turn laundry gray, leave soap scum on bathroom tile and produce soap residue that irritates the family's skin. Other minerals create red, brown, green and black staining and "rotten egg" odors in drinking water. City water purification does not seem to completely solve the problem either and many cities chlorinate drinking water only to kill bacteria.