http://www.space.com/34811-mars-ice-more-water-than-lake-superior.html

A giant deposit of buried ice on Mars contains about as much water as Lake Superior does here on Earth, a new study reports.

The ice layer, which spans a greater area than the state of New Mexico, lies in Mars’ mid-northern latitudes and is covered by just 3 feet to 33 feet (1 to 10 meters) of soil. It therefore represents a vast possible resource for future astronauts exploring the Red Planet, study team members said.