Water is a basic element of all life.
Over 70 percent of the human body is made up of water. While a human being may survive without food for several days, water deprivation can kill a person within a matter of hours. Water is also a requirement for the most basic activities vital to sustaining human life, including agriculture, cooking, and sanitation. Yet while water sustains life, it can also bring death if contaminated. Some of the deadliest diseases, which kill millions around the world each year, are carried in unclean water.