Earth is a planet rich with water, a compound essential to all living things. However, fresh water is a limited resource. So, where is all the water? Seventy percent (70%) of the Earth’s surface is covered with water and when viewed from space, our planet appears blue with a plentiful supply of water. However, clean, fresh water for drinking and irrigation is a scarce and valuable commodity in many parts of the world. Even though water is abundant on our planet, only a very small percentage can be used by humans and other organisms.