Most wells from which water was sampled did not have sanitary seals and very few were grouted. This may have contributed to the number of detections of bacteria. It is uncertain whether the bacteria detected are the result of widespread aquifer contamination or site-specific factors. Studies began in 1991 in the Lower Susquehanna River Basin study unit, hereafter termed the study unit. The occurrence and distribution of bacteria in ground water are important water-quality issues in the study unit.
Ground water is an important source of household supply in the study unit.
To estimate the number of households and private wells, the number in each county was multiplied by the fraction of each county in the basin. Using this estimation, about 800,000 households and approximately 300,000 private wells are in the basin. Therefore, approximately 38 percent of the households in the study unit depend on ground water from private wells for water supply. Private water-supply information from the 1990 U.S. Bureau of the Census for counties in the Lower Susquehanna River Basin study unit. This report describes and explains the bacteriological quality of raw water from private wells used for household water supplies in the Lower Susquehanna River Basin study unit.