This term is defined as taking water from a water system and not returning it to the same system. Naturally, all water sources will replenish themselves over time through the hydrologic cycle. However, when water is drawn at a rate where more is being taken than put in, it can create problems. Only 2.5% of the water on earth is freshwater. Of this amount of freshwater, only 1% is affordable and attainable to humans today.