A real nice horde of information on water from the USGS Water Science School.
As you know, the Earth is a watery place. But just how much water exists on, in, and above our planet? About 71 percent of the Earth’s surface is water-covered, and the oceans hold about 96.5 percent of all Earth’s water. But water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers, and even in you and your dog.
Water is never sitting still, though, and thanks to the water cycle, our planet’s water supply is constantly moving from one place to another and from one form to another. Things would get pretty stale without the water cycle!
Retrieved July 14, 2014 from http://water.usgs.gov/edu/earthhowmuch.html