There are different sources of water. About 75 percent of the earth’s surface is covered with water. But all water is not suitable for drinking. It should be conditioning before use. Water is essential for every living thing on the earth. The sources of water mainly classified into four groups.
Surface water means the water that are present on the surface of the earth. The main sources of surface water are rain and snow. This class of water further can be divided in to two classes’ static and moving surface water. River, streams and canal water are moving surface water; on the other hand lake and ponds water are static surface water. Sea water is not included into surface water. Surface water is contaminant with turbidity, suspended solids, micro-organism, bacteria, Ca and Mg salt, bad order, taste and color.
Part of the rainwater falls on earth soaks through the soil. This water stock up in the ground as soil moisture. The ground water are spring water, sinking tube wells. There are no turbidity, microbial in ground water. But it is contaminants by higher hardness, dissolved gasses.
When atmospheric water vapor precipitates and become heavy enough to fall earth as droplet is called rain water. Rain water is weakly acidic because it is absorbs carbon-di-oxide. Industrial uses of this water is little amount.
Sea water has salinity. The use of this water is limited. It is very hard to treatments. Oxygen and carbon di-oxide also dissolved in it.