Fluoride concentration has been quantitatively determined for ground water samples from Varattupallam and Kumbaravani Pallam watershed of Bhavani Sub-Basin. The results do not indicate large variation. A minimum of 0.2 mg/l to maximum of 2.0mg/l in the post monsoon and a minimum of 0.2 mg/l to a maximum of 11.00 mg/l in pre monsoon samples have been observed in the study area. Most of the samples show <1.5 mg/l except in few locations. The sample near K.T. Ammankoil Pudur (Loc. No. 25) and Kattupalayam (Loc.No.46) have recorded slightly higher concentration >1.5 mg/l during the post monsoon, where as during pre monsoon, the sample near Palliapalam recorded anomalous high concentration of fluoride (11.00 mg/l). The studies of fluoride concentration do not indicate any significance alarming impact except the area near Palliapalayam. The possible source can be attributed to the influence of fluoride bearing minerals in the country rock Fissile Hornblende Biotite Gneiss.