Potable water quality in rural Georgetown County.

Drinking water supplies of 161 rural communities, in Georgetown County, South Carolina, were randomly selected for sample collection. The analysis showed that most of the waters were slightly acidic. Low, but acceptable concentrations of chloride, copper, fluoride, sodium, cadmium, nitrate and phosphate were found. A few water samples showed higher then recommended levels of arsenic, mercury, zinc and lead. Although only 2% of the samples exceeded the mandatory limit of 0.05 ppm for arsenic, 72% exceeded the recommended level of 0.01 ppm. The mandatory limit for manganese was exceeded in 37% of the waters while 88% exceeded the limit for iron. The high iron content was generally responsible for the high turbidity found in 45% of the samples. The well depth and the consumer income had some bearing on water quality. Statistical evidence suggested that septic tank seepage was partially responsible for nitrate, phosphate, iron and arsenic contamination of shallow water supplies. Lead concentrations appear to vary according to the plumbing used and the pH of the waters.