The Water Cycle: When water evaporates from water bodies (such as oceans, lakes, and rivers), it forms clouds and returns to earth as precipitation (rain or snow). The amount of water that evaporates each year and the amount that falls back to the ground are virtually constant, meaning that the amount of water on earth does not change. So if a drought occurs in a specific region, it is not because the world’s rainfall for the year is less, but because the water is falling somewhere else on earth. Water reuse solutions attempt to assist Mother Nature in the natural water cycle process by speeding up the process to account for growing demand of water.