No one knows for sure if water is available at the lunar poles. There are strong indications of hydrogen but we don't know in what form it may be, whether it's in the form of easily harvested ice or if it's chemically bound to the soil or rocks.

My design assumptions, for what they're worth, are based on the optimistic view that ice is available. However, until we know for sure, all of this is just speculation. The best way to find out for sure would be to send one or more robotic landers to the areas where ice may exist and take samples, perhaps with the aid of rovers. The Soviets landed unmanned probes on the moon in the 1970s including at least one with a rover. Luna 20 and Luna 24 actually returned soil samples. I don't see any insurmountable technical problems with us doing that today. Of course, finding the funding is an issue but that's always the case.