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. About 50 percent of the waterborne disease outbreaks in this country since the early 1900's were caused by contaminated ground water that was untreated or inadequately treated. Water sources that are free from disease-causing impurities and other harmful substances are said to be potable water sources.
Potable water is water fit for human consumption.
Each State has its own criteria defining the potability of water. Bacterial potability of water is determined by testing for indicator organisms. The indicator bacteria were the coliform bacteria group and the streptococcal bacteria group. The presence of E. coli in ground water indicates that the contamination of the water supply is fecal in origin. Sources of fecal-indicator bacteria include septic system failure or improper septic system construction or design, feedlot or field runoff, manure application on fields, and application of municipal sludge.