Without healthy water for drinking, cooking, fishing, and farming, the human race would perish. Clean water is also necessary for recreational interests such as swimming, boating, and water skiing. Yet, when Congress began assessing national water quality during the early 1970s, it found that much of the country's groundwater and surface water was contaminated or severely compromised. Studies revealed that the nation's three primary sources of water pollution—industry, agriculture, and municipalities—had been regularly discharging harmful materials into water supplies throughout the country over a number of years.