People can not live in a planet which has a desert-like rocky environment. However, scientists grasp the evidence that a large amount of water is buried in the deep underground of Mars.
Roberto Orosei of The Guardian the Italian National Astrophysics Laboratory (INAF) video and explanation below.
As a result of years of observation, we discovered that a large amount of water is buried in the place of 1.5 km underground from the ice present in Antarctica.
The groundwater has spread to such an extent that it can be called a lake and contain a large amount of salt. The fact that the ice on the upper side is transparent.
If you want to collect water, you have to drill a 1.5 km thick ice with a drill. It is a very difficult task with the technology of the present earthling people.
In addition, the repercussions of the radio wave radiation from the sky, due to its high dielectric constant only a particular area. There is a layer of water found in the basement. Mars has a thin atmospheric layer, the earth's surface is very cold and vaporized moisture escapes to space. However, there is a possibility that the water that once was frozen from the cold and the environment of Martian full of perchlorate.
Perchlorate is also a chemical substance that can also act as an oxidizing agent for explosives and rocket fuels. There are microorganisms living on the earth with that energy.