The research presents water quality analysis of Bhadravathi in Karnataka State, India. Fourteen physico-chemical and biological parameters were considered for the analysis. The raster maps created using GIS are used to represent the spatial distribution of the parameters for both pre and post-monsoon seasons. Using physico-chemical parameters, Water Quality Index (WQI) was determined. The WQI shows 11% of the surface water samples fall under very good category during pre-monsoon and 78% in post-monsoon. The water sample at New Bridge site shows sign of pollution throughout year with WQI in the range 50-100 and hence unfit for use. In groundwater samples, 20% of samples in the pre-monsoon and 50% samples during post-monsoon fall under good quality. 50% of water samples during pre-monsoon and 60% of samples during post-monsoon fall under good category and water sample at Haladamma temple are found unfit. Further, QUAL2K model predicted the DO and BOD values considerably well along the Bhadra River from Lakkavalli to Bhadravathi Town. However, the Streeter Phelp’s model estimated higher DO as compared to QUAL2K model. This is due to provision of outfall effect in Streeter Phelp’s model.