ABSTRACT
Water is always in motion, and the hydrologic cycle describes this movement from place to place. The United States relies heavily on its surface water supplies, accounting for 79% of all the water usage. The remaining 21% of the US water usage is from groundwater. The term aquifer is given to underground soil or fractured rock through which groundwater can move. True national drinking water standards were not established, however, until 60 years later with the SDWA. Originally, the SDWA focused primarily on treatment as the means of providing safe drinking water. Drinking water standards are regulations that the EPA has established to control the concentration of contaminants in the US drinking water supply. In most cases, the EPA delegates responsibility for implementing drinking water standards to states and tribes. Drinking water standards apply to PWSs, which provide water for human consumption through at least 15 service connections or regularly serve at least 25 individuals.
