Kalingarayan canal is one of the historically important irrigation water sources in Erode District. Recently the water in the channel being polluted by letting out untreated tannery and textile effluents. It has been decided, therefore, to carryout a study on the quality of water and its pollutional load. The quality of water is determined by examining physicochemical and biological characteristics. In order to present a simple and comprehensive Water Quality Index (WQI) that could be understood by nontechnical experts and common man, the standard NSF method has been adopted. An alternative WQI omitting Temperature, BOD and phosphates has been evaluated and the correlation between NSF index and this new index has been good. The study revealed that the channel water is highly polluted and could be used for irrigation only.