The availability of water in terms of both quantity and quality is essential to the very existence of mankind. Earlier people recognized the importance of water from quantity view point. Recognition of the importance of water quality developed more slowly. In the field of water resource management, information on the water quality is an essential input. Changes in water quality can be the result of domestic, industrial or agricultural discharges. The number of physical and chemical parameters such as pH, DO, alkalinity, conductivity, total solids, hardness, inorganic and organic trace elements etc. That needs to be monitored for proper assessment of water quality of any water resource is very large. In water resource management, where classification and comparison of different water resources on the basis of water quality is often requisite, it will be more convenient to integrate the data pool in some way to produce a single number. Water Quality Index (WQI) achieves these objectives and is of great value in water resource management.