Water is the most abundant and the most important medium on Earth as well as in the human body. Because water is an universal solvent, all the other substances are found in it, dissolved to different degrees and that is why pure water can not be found in nature. Mineral content of natural waters (and waters in our bodies) varies.Water is fundamental to all the living creatures and in human body it is the primary component of every bodily fluid and involved in almost every bodily function.Water requirements depend on our diet, activity level and climate in which we reside.Regardless of our personal water requirements and geographical location of our residence – how to keep water clean and safe (how to heal polluted bodies of water) for human consumption should become everybody’s concern because there is no optimum health without clean water. Most of the tap water in U.S. comes from surface sources (rivers, streams and lakes) and the rest is from groundwater (subterranean reservoirs). Water from both sources (surface and subterranean) most likely contains many environmental pollutants: animal wastes, local fertilizers (i.e. nitrates), insecticides, industrial chemicals and wastes, air pollutants (i.e. lead and radon), toxic organic chemicals, petroleum spills.All the city tap water is treated in local treatment plants which in many cases use an obsolete process of settling tanks, filtration through sand and gravel and adding chemicals to purify the water for human consumption.After the treatment our “drinking” water might contain all or most of the following, most likely hazardous chemical additives: chlorine (to kill the germs), fluoride (to prevent tooth decay), calcium hydroxide or other alkaline substances (to change pH of the water and prevent pipes from corroding).Unfortunately, all of these processes may still not clean up the water of all the environmental pollutants.To make things worse, chlorine and other chemicals are likely to react with other organic chemicals in the water and form new substances that may act as carcinogens. Even some water pipes might contribute toxic chemicals or metals.It doesn’t come as surprise that bottled water is one of the fastest growing businesses all around the world. Anyhow, the synthetic materials, used for manufacturing of plastic bottles are also a growing concern, so – home-filtered tap water (using solid carbon filtration) is at the moment our safest source of fresh drinking and cooking water.