The greatest risk to the earth's water supply is water pollution and over use of water due to human interventions. Only a small amount of water is available for human consumption,rest is saline in taste, which makes it unsuitable for human consumption. The pollution makes water non-usable and this is going to become a serious problem in future. The pollutants such as chemicals, fertilizers, pesticides and industrial and household waste makes water toxic in nature.ground water is connected to the rivers, streams and lakes. The over consumption of groundwater lowers the amount of water present in lakes, streams and river and the supply can be diminished.