Groundwater sources play an important role in meeting the day today needs of the present generation for various activities such as domestic, industrial, commercial and agricultural. These sources are to be protected from pollution to meet the essentials of the future generation. Frequent monitoring of the ground water source plays an important part. The aim of this study is to analyze the quality of the ground water in and around the open dumpsite near Sathyamangalam town in Erode district and to identify the variation in concentration with respect to time. Groundwater samples were collected from twenty-one locations in around the open dumpsite and analyzed for the important parameters such as pH, Electrical conductivity (EC), Total Alkalinity (TA), Total Hardness (TH), Total Dissolved solids (TDS), Calcium (Ca2+), Magnesium (Mg2+), Chlorides (Cl-), Sodium (Na+), Potassium (K+), Nitrates (NO3-) and Sulphates (SO42-). Water Quality Index (WQI) was used to identify the quality of water for drinking. From the results obtained, it is inferred that WQI changes with respect to different seasons and different time periods for the same season. Majority of the samples are of poor quality with respect to drinking water quality index. Gibb’s plot, Wilcox diagram and United States Salinity Laboratory (USSL) diagram are used to assess the suitability of groundwater samples for irrigation purpose. Most of the samples are good for agricultural use. Hence frequent and continuous monitoring of the groundwater quality is necessary to identify its suitability for drinking and agricultural purpose.