Several countries are either dropping fluoridation, or are banning its use. Over 66,000 different chemicals are in use today, and they can potentially affect our water supply. Many of these chemicals have never been tested for safety. Fluorides have been called into question in a variety of health concerns ranging from cancer to arthritis. A number of pollutants in drinking-water sources have been linked with behavioral problems in children and adults.
Many people are allergic to chlorine and other contaminants.
Pollutants are also linked to increased cancer risk. Water is a natural solvent that eventually dissolves almost anything. The molecular properties of water cause it to act like a magnet and strip particles from other materials. This gives water the power to dissolve and clean things, but it also gives it the power to pick up a lot of undesired materials between the water source and your faucet. These standards specify the allowable parts per million for a given type of material.