South Kalimantan is a province of Indonesia. It is located in Kalimantan, the Indonesian territory of Borneo. About three quarters of the province is flat and less than 100 m above sea level, while about 8,000 km² are swampland. It makes the water conditions in south Kalimantan is swamp water. However, due to the amount of the swamp water, the water is used as a source of public drinking water. These conditions resulted in many residents have abnormalities in the teeth. These can make a demineralization of the tooth resulted the dental erosion. The relation between water condition in south kalimantan and demineralization of tooth that can caused the dental erotion were never been investigated, thus our study aimed to evaluate the potential effect of water in South Kalimantan on demineralization of dental which can caused a dental erosion by measuring their correlation. From our resluted, we found that there are a correlation between mineral cocentration of the tooth and day in different pH, and a correlation between minerals in different pH. The results of this study concluded that chronic exposure to acid water can caused demineralization of the tooth and resulted a dental erotion. Index Terms—Acid Water, Dental Demineralization, Dental Erotion, tooth.