So far, everything that has been discussed concerning the implementation of the Mars base from making rocket fuel, rover fuel, and oxygen to producing plastics, bricks, mortar, and pottery; to growing crops, to sealing leaks and hardening soil with artificial permafrost, all require water.   If human civilization is ever to flourish on Mars, a way must be found to obtain water.

    The first step in tapping a water source is planting the permanent base near a likely water source, which on Mars would be the Northern Hemisphere.  In early Martian history, it is believed that a vast basin in the Northern Hemisphere was filled with water.  The remnant of this water is the northern polar cap, which is made of water ice.  In addition, water could be traced on the subsurface level.   If these pools of water exist below the surface, this would be a direct, but difficult water source to tap. Another possible way to find water would be to find brines. Saturated salt solutions can be liquid at temperatures as low as –55 degree Celsius, which means that even without geothermal heat, such liquid brines, protected from evaporation by a modest layer of soil or ice, could exist on Mars today very close to the surface.

    Martian soil, as shown by the Viking landers, has some water in it.   These missions showed that the soil was one percent water.  However, these tests were skewed by the fact that the samples were surface samples, they were held at high temperature, and were only tested for thirty seconds.  Therefore, the actual amount is probably three percent.  However there are other materials, like salts and clays, which can hold much more water (gypsum and smectite clay).  Whatever the amount, it only takes heat to release the water.  There are two ways to do this.   One way is to truck damp soil to an oven which heats the soil and collect the steam to condense it into water.  The dehydrated dirt is an inconvenience, but the power consumption of this system is so low, 3.5 kWh per kg water, is worthwhile.   Furthermore, the reactor is used to heat the dirt, 14,000 kg of water per day.   However, there would be 462,000 kg of excess dirt.  The other alternative is to bring the heater to the dirt.  This method would require a portable oven on a truck powered by a radioisotope thermoelectric generator.  The excess energy from powering the truck would produce 42 kg of water per day. This output is so small comparatively that it would only be useful to an exploratory team.  Another way is to use a microwave heater to heat the soil below the moving unit, collecting steam as it moves. However, since thermal power is more available, this method is not efficient.   Nevertheless, this system would be beneficial in that it can be tuned to heat only water molecules.  In addition, if the water concentration is high and the ground is frozen, the microwave method is best.

    An even better method of water extraction would be utilizing a 0.1 mm thick polyethylene, transparent tent which weighs about 38 kg on Mars.  This 25 meter diametered sphere would be able to generate 500 W/sq. meter and could be enhanced through lenses adding an addition 200 W/sq. meter.  Using a cooled plate in one corner of the tent, a mass of 224 kg of water could be extracted from the top half centimeter of soil through the method of producing frost, like in a freezer.  Then, the tent could be moved by a rover team and the area just harvested could rehydrate and be harvested an infinite amount of times.

    A different approach would be taking the water straight from the atmosphere, however, one kg of water can only be extracted from one million cubic meters of atmosphere.  Due to the specs on a compressor designed to extract the water, the per kg cost of energy for the atmosphere extraction is 103 kWh and the terrain extraction would require only 3.5 kWh of energy. However, the compressor might have some advantage besides the less beneficial energy cost.   Argon and nitrogen will be produced in the compressor extraction, which are both usable materials in the Martian base.  However, a newer form of atmospheric extraction has been conceived by Adam Bruckner, Steven Coons, and John Williams of the University of Washington. This new idea is a zeolite sorption bed.  Zeolite can absorb up to 20% its own weight in water and can be relieved of that fluid through baking it out at a cost of merely 2 kWh per kg of water. After which, the zeolite can be reused.   Then again, the zeolite sorption bed has to be quite larger than the surface extraction tent.  But, this atmospheric extractor can remain stationary and not need a mobile power source as it will be connected directly to the base power generating (it will only make 90 kg of water a day unfortunately in place of saving 8 kWe needed to run the fan). The fact that no digging is required and the raw material, air, is infinitely renewable which make the system available to complete automation; making it quite attractive.  Anyway that water is extracted from Mars to support the Martian outpost, this resource will be able to effectively support some form of greenery on the planet; the first step to evolving Mars into an inhabitable planet.