Water quality parameters viz. air temperature (15.21 0 C -36 0 C/16.71 0 C - 39.42 0 C), water temperature (13 0 C-32.42 0 C/15 0 C-32.8 0 C), depth (42cm-69.08cm/ 25cm-121.92cm), turbidity (3.88-46.27NTU/3.67-69.39 NTU), salinity (0.10-0.31ppt/ 0.10-0.37ppt), electrical conductivity (0.101-0.172mS/cm/0.114-0.279mS/cm), TDS (49.63-111.78 mg/l/57.64-177.01mg/l), pH (7.92-9.82/7.80-9.09), free CO2 (0-19.22mg/l/0-15.32mg/l), DO (6.82-9.90mg/l/4.65-9.40mg/l), carbonate (0-18.38mg/l/0-20.63mg/l), bicarbonate (60.99-170.70mg/l/77.62-168.70mg/l, chloride (7.41-12.35mg/l/9.59-19.60mg/l), calcium (6.85-38.50mg/l/11.81-140.49mg/l), magnesium (4.62-7.22mg/l/3.86-39.05mg/l), total hardness (40.29-125.50 mg/l/56.61-511.05mg/l), BOD (3.12-5.79mg/l/1.31-16.21 mg/l), COD (17.74-75.42 mg/l/ 26.57-73.03mg/l), sodium (14.2-22.5mg/l/12.2-30.9mg/l), potassium (1.83-4.17mg/l/2.25-6.21mg/l), phosphate (0.048-0.233mg/l/0.008-0.603mg/l), nitrate (0.13-1.3mg/l/0.11-4.08mg/l), sulphate (1.60-19.19mg/l/1.36-15.70mg/l), silicate (0.14-4.23mg/l/0.27-7.05mg/l), iron (0-0.65/0-0.40mg/l), copper (below detectable limit) and zinc (below detectable limit), of lake Surinsar-the only source of drinking water to the inhabitants of the Surinsar village, have been reported monthly, during the year 2002-03/2003-04. WQI range falls from poor (70.45, December; 73.55, October; 74.4, November and 74.56, September/ 74.52, January and 75.36, September), very poor(82.54, February; 89.25, May; 80.76, August and 78.86, January/ 80.89, February; 98.25, April; 80.03, June; 82.26, July; 86.55, October and 83.03, November) to unfit (100.44, June; 101.9, July; 103.86, April and 119.5, March/ 103.73, May; 108.28, March; 122.56, August and 103.72, December). Comparison of range of various water quality parameters of Surinsar lake water, with national and international standards has also revealed that most of these parameters are beyond permissible limits. This clearly indicates the unsuitability of raw water, generally consumed by local inhabitants, for human consumption.