Groundwater, the largest source of fresh water on Earth, represents more than 90 percent of the readily available freshwater reserves and is therefore of vital importance to meeting the water needs of up to 2 billion people. It constitutes the primary source of water for up to 50 percent of the American population, a figure that rises to 95 percent in rural areas. Groundwater is also the safest and most reliable source of fresh water. At the same time, this water can be used to produce geothermal energy and save energy by using heat pumps. Read more