Water is one of the most plentiful and essential of compounds.
It is vital to life, participating in virtually every process that occurs in plants and animals. The basic source of water is rainfall, which collects in rivers and lakes, under the ground, and in artificial reservoirs. Water from under the ground is called groundwater and is tapped by means of Wells. Most often water must be raised from a well by pumping. Water that collects in rivers, lakes, or reservoirs is called surface water.