[Saulot]

Well, somewhat tangental, but as good of a time to discuss it as any... this far off world may have the same problems as Mars does. The problems with colonizing Mars are twofold, and neither of these have anything to do with water.
1. Mars has a very limited atmosphere.
2. Mars' core is not molten.
(Let's ignore the poisonous atmosphere, the low pressure, and the dangerous gale winds and extreme dust storms, for a moment.)

These issues are both very related, and two is by far the more important one. The molten core of earth both creates our atmosphere, and protects it from solar wind, and protects us from radiation from space. Most of our atmosphere is created through the result of rather continuous (on a geological time scale) volcanic eruptions. (The rest comes from comet impacts.) The second part is that because our core is still molten, the iron inside it spins, creating our magnetic field, which protects the planet and the atmosphere, and consequently life since both the magnetic field and the atmosphere on earth prevent much radiation from reaching the ground. Since Mars is both smaller, and farther from the sun, it has cooled quicker. Without that molten core, maintaining an atmosphere on mars will be difficult, and without both field and atmosphere, there will be very significant amounts of radiation. I suppose one could survive underground on mars, but I don't imagine that would be any different from living in a deep underground bunker here on earth.