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Seasonal variation on physico-chemical quality of well water at Eloor industrial area, Kerala was studied. A total of 100 samples, 25 each during four different seasons, viz. summer, pre- monsoon, monsoon and post monsoon were collected during the year 2009 and analyzed for temperature, pH, total hardness, Chemical Oxygen Demand, concentration of nitrate, fluoride, iron, heavy metals like lead, mercury, zinc, and cadmium. Significant difference between seasons was observed for temperature, Chemical Oxygen Demand, concentration of nitrate, zinc and cadmium. Highest temperature (28.96±0.16) was recorded during pre- monsoon. Chemical Oxygen Demand and zinc concentration was recorded maximum during summer (150.56±14.07, 0.21±0.04 mg/l respectively). Highest nitrate (5.96±1.10 mg/l) and cadmium (0.05±0.005 mg/l) concentrations were recorded during post monsoon and monsoon respectively The results were compared with WHO guidelines, 2006 and IS: 10500, 1991, desirable limits for drinking water and found that pH, total hardness, concentration of iron, lead and cadmium were not within the acceptable rage.