PhysOrg says there’s liquid water on Mars (great!) but (aw!) it’s too far underground to tap:
The data from NASA’s Insight lander allowed the scientists to estimate that the amount of groundwater could cover the entire planet to a depth of between 1 and 2 kilometers, or about a mile.
While that’s good news for those tracking the fate of water on the planet after its oceans disappeared more than 3 billion years ago, the reservoir won’t be of much use to anyone trying to tap into it to supply a future Mars colony.
It’s located in tiny cracks and pores in rock in the middle of the Martian crust, between 11.5 and 20 kilometers below the surface. Even on Earth, drilling a hole a kilometer deep is a challenge.
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The new paper analyzed the deeper crust and concluded that the “available data are best explained by a water-saturated mid-crust” below Insight’s location. Assuming the crust is similar throughout the planet, the [University of California, Berkeley] team argued, there should be more water in this mid-crust zone than the “volumes proposed to have filled hypothesized ancient Martian oceans.”
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You can read more of the Mars findings here, in Proceedings of the National Academy of Sciences.