The document discusses water purification and distribution. It begins by describing the three forms water can take and the water cycle by which salt water is converted to fresh water through evaporation and precipitation. It then lists three ways to obtain fresh water and four characteristics of safe drinking water. The document also names two types of water filters and states that water is most dense at 4°C. It lists four common water impurities and explains how to remove two types of water hardness. In closing, it summarizes the local water treatment and distribution process involving dams, pumps, treatment plants, and pipes.