Fresh water makes up only 3% of the water on Earth, with the majority being salt water in the oceans. Fresh water exists as icecaps and glaciers, groundwater, and surface water in lakes, rivers, and streams. The document identifies that we are part of the Mississippi watershed and Tennessee River tributary. It describes groundwater as water stored underground in aquifers and sediments, below the water table. Porosity refers to the space between particles in rock, while permeability determines how much water the rock can hold. A video from Unicef discusses global fresh water issues.