When these pollutants get into natural water sources, they harm the plants and animals that live there. Wastewater from homes is sent to wastewater treatment plants through large pipes called sewers. Businesses and industries sometimes pollute water with chemicals that they dispose of improperly, but nature also pollutes water with animal waste , dead leaves, and other naturally occurring events. So all water that people use to drink must be cleaned in some way. The Hydrologic Cycle Water is all around us in one form or another, constantly moving constantly changing.
Water vapor travels up into the atmosphere where it cools into clouds.
This process is called Condensation. As plants grow, they give off water vapor too. This process is called transpiration. Precipitation When the clouds get heavy, the water forms into drops and falls back to earth as rain, snow, sleet, or hail. These forms are called precipitation.