Water Use in the United States Source: ChemCom: Chemistry in the Community 97 percent of the world's water supply is difficult, if not impossible, to obtain or to use because it is in the oceans or in the form of glaciers and ice caps. Scientists are exploring methods of conserving and protecting the rest of Earth's water supply for the growing population. According to the information provided, which of the following activities most directly affects the water supply? A. drinking and cooking B. growing all types of food C. irrigating field crops D. producing energy and manufacturing E. flushing toilets and bathing