Answer: enough water to fill 360,000,000,000,000,000,000 gallon-sized milk containers!
The ocean covers more than 70 percent of the surface of our planet. It's hard to imagine, but an astounding 97 percent of the Earth's water can be found in our oceans. Of the tiny percentage that's not in the ocean, about two percent is frozen up in glaciers and ice caps. Less than one percent of all the water on Earth is fresh. A tiny fraction of water exists as water vapor in our atmosphere.
According to the U.S. Geological Survey , there are over 1,386,000,000 cubic kilometers of water on the planet. A cubic kilometer is the volume of a cube measuring one kilometer on each side. Almost all of this vast volume of water is in the ocean, and it's enough to fill all the gallon-sized milk containers mentioned above.