Dr. John C. Geyer and Dr. Charles E. Renn, professors of sanitary engineering at the Johns Hopkins University, discuss the municipal and industrial demands on water. Dr. Geyer explains how a city water meter works and shows the resulting graphs that predict the time of greatest water use. Dr. Renn displays examples of common products and tells how much water is required to manufacture each. He also discusses rainwater, wells, rivers, lakes, and reservoirs as sources of water and how river water can be used, treated, and returned. A film clip documents the formation of a river. Using a diagram, Dr. Geyer explains municipal water purification and waste treatment processes. Dr. Renn discusses industrial waste disposal and how it can cause stream pollution unless treated by a waste control plant, such as that of American Cyanamid Co., in New Jersey. Dr. Geyer notes the growing conflict in the American southwest over water use between industry and agriculture. Dr. Renn concludes that increasing water demands require either stopping growth or building more dams and evaluating priorities for use, such as recent multiple use (recreation, power, water control) projects of the Tennessee Valley Authority (TVA).