Abstract: The study presents results of the research on water quality of the Kashaf River in the period from 1996-2005. Applied methodology enclosed ten different water quality determinants classifying according to the existing Iranian regulations, as well as the Water quality index. The water quality of the Kashaf River in investigated period has been differed depending on the measuring location and the hydrological situations. As the drinking water source in some part, the Kashaf River had adequate environmental characteristics. The results have been showed that different indicators of river water quality have not the same ecological importance. The water quality index has been suggested as a simple way for the evaluation of water quality monitoring. Also forming the PC register of pollutants is necessary for providing of dequate preventive measures.