Water deposits near Mars' equator are "exactly" where rover missions now on their way will land, said space scientist Bill Feldman, of Los Alamos National Lab, in New Mexico.
He presented the map at last week's Sixth International Conference on Mars in Pasadena, Calif.
Alongside astrobiologists' conjectures about the possibility that water resources serve life on Mars, planetary scientists have long considered whether Martian water could be used by future explorers.
Near the poles, ice deposits are substantial, with about a pound of water within every two pounds of soil. In many cases the ice deposits are within only a few inches of the planet's surface.
"Understanding water on Mars is key to understanding the planet," planetary scientist Laurie Leshin, of Arizona State University, in Tempe, Ariz., told USA Today.