T he research area is located in the Subdistrict of Manggar that administratively entered into the district of East Belitung, Bangka Belitung province. Geographically the study area is located at 20 52' 23,42'' LS - 20 55' 54,99'' LS dan 1080 11' 37,35'' BT - 1080 17' 36,26'' BT. Groundwater at the site of the research included in the unconfined aquifer into the aquifer (aquifer free) which has groundwater level distribution of sea level ranges from ± 1.11 to 15.21 meters (dml). The results of the analysis of ground water samples which is conducted in the laboratory to determine the concentration of anions and cations, Facies chemical research area of groundwater and surface water can be grouped into 5 (five) facies, that is: facies Na++K+, Cl- (Natrium, Chloride), facies Ca2+, HCO3-+CO32- (Calcium, Bicarbonate), facies Na++K+, SO42- (Natrium, Sulfate), facies Ca2+, SO42- (Calcium Sulfate), facies Na++K+, HCO3-+CO32 -(Natrium, Bicarbonate). By using Ogata method (1970) can be seen the value of the initial concentration and final concentration using a permeability of 2500 meters/ day of contaminants Iron (Fe) of the hydraulic gradient in the study area consists of the hydraulic gradient SG.6-SG.5 to a final concentration of substances polluter is 0.18499 mg /L during the period of 365 days, on SG.4-SG.2 during the period of 365 days this concentration of 0.18492 mg / L, SG.3-SG.2 during the period of 365 days this concentration of 0.05311 mg / L concentration is quite normal in the raw water quality and drinking water quality, on SG.5-SG.2 during the period of 365 days this concentration 21.0294 mg / L is quite beyond normal limits on water quality standards and drinking water quality.