In this study waste heat from the steam-electric generating plants using fossil fuel was assessed and the cost for treating the waste heat was estimated. Major waste heat-producing industries are: fossil fuel (oil, gas and coal), and nuclear power generating plants, steel mills, petroleum refineries, chemical plants, pulp and paper mills and distilleries. An increase in stream temperature reduces its waste assimilation capacity. Excessive increases or reductions in ambient water temperatures by other than climatological causes can be defined as thermal pollution. Thermal pollution from steam-electric generating plants is caused by the heat rejected from waste steam to cooling water that is discharged to the stream. The effects of thermal pollution are detailed. Power generation and trends in power generation are presented. Quantities of heat wasted are discussed. Methods for controlling thermal pollution are discussed.