Not a lot of good reservoir sites on Mars

For those planning a trip to Mars….

Evidence shows that more than 3 billion years ago Mars was wet and habitable. However, this latest research reaffirms just how dry the environment is today. For life to exist in the areas we investigated, it would need to find pockets far beneath the surface, located away from the dryness and radiation present on the ground.

So, not a lot of good reservoir sites, really no choice other than (unsustainable?) groundwater pumping.