Water and Its Importance Water is the most important substance on earth. It is the beginning of all life, and sustains life in all organisms. Most organisms are predominately made up of water and they depend on it from their day to day life. Almost every aspect of natural life traces back to water. Needless to say, it is an extremely important substance. Water exists in all three states of matter: liquid, solid, and gas. It has many unique properties that enable life to continue as we know it. No other substance on earth is like it. It is an odorless tasteless liquid, a compound of hydrogen and oxygen. Its hy