The availability of water for future astronaut explorers or even, eventually, colonizers on Mars will be critical.
Water can be used to make rocket fuel and oxygen through electrolysis, but drinking water is a fundamental necessity of human life.
While the Curiosity rover discovered what had been oases of fresh water 3.5 billion years ago, which might have hosted life, finding potable water for future human explorers or colonists will be vital.  
Early on, NASA announced that evidence of fresh water had been found by the Opportunity Mars rover in 2013.
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Scientists of the U.S. Geological Service may also have discovered signs of potable water on Mars.
The scientists had studied images of the erosion of rocky ledges using the CRISM spectroscope on board the Mars Reconnaissance Orbiter (MRO) and came to the conclusion that water ice, which may be usable by astronauts, was causing the erosion they observed.
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This study led researchers to believe there was much more water on Mars that had been previously thought.
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Large Ice formations were also located using the Shallow Radar on the MRO.  
Upon zeroing in more intensely on eight locations in Mars’ mid latitudes with the MRO’s High Resolution Imaging Science Experiment, scientists discovered layers of water ice, some of which were 90 meters thick.
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In some places the ice was just a few meters below the surface.
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As one NASA researcher put it, it would be possible for an astronaut to exit their spacecraft with a shovel and a bucket to get the water they would need.
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Themis, another system on board MRO, also indicated that the presumed water was in a thick layer, not a thin crust near the surface of Mars.
American researchers have reported that the Arcadia lowland region on Mars would be a favorable place for a manned landing.
It promised large reserves of water ice, which astronauts would be able to reach with a shovel just centimeters below the surface.
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It was not yet clear whether this water would be potable.

Warning: these questons and answers are not all representative of the way questions will be asked and answered in the pilot, because some questions are compound and some answers do not include citations.

Q: What can be obtained by processing the water found on Mars?
A: Oxygen and rocket fuel can be obtained through electrolysis.

Q: What areas on Mars seem to be promising for extracting water ice?
A: Arcadia and the several locations in the mid latitudes of the planet.

Q: How deeply below the surface of Mars are some of the ice deposits?
A: Some are just a few meters below the surface.

Q: Has the thickness of the ice been determined?
A: How thick might it be? - Some deposits were as much as 90 meters thick.

Q: Given the accuracy of the present data, how easily could an astronaut obtain water on Mars?
A: An astronaut could dig a short distance into the ground and fill a bucket with ice for water.

Q: Which spacecraft were used to obtain information on water on Mars?
A: The rovers Curiosity and Opportunity on the Mars Reconnaissance Orbiter above the planet.

Q: Is water typically in a thin layer under the Martian surface?
A: No, the Themis system on board MRO indicated it was in a relatively thick layer.

Q: Were the one-time oases of fresh water identified on Mars relatively recent?
A: Unfortunately no, they were approximately 3.5 billion years old.

Q: What led the U.S. Geological Service scientists to infer the existence of water on Mars?
A: Erosion in rocky ledges seen by the CRISM spectroscope on the MRO.

Q: Have scientists selected a favorable landing area for astronauts visiting Mats?
A: If so, where? - The scientists like Arcadia lowland region, with its large reserves of accessible water ice.