“The water that comes up from these geothermal hot spots is full of minerals that clog up pipes and other factors that can eat through pipes.”
Not if you install it as a completely sealed system in your own yard. Why more folks do not do this I have no clue, it is almost free heating and cooling for your home.
I don’t think you’re talking about geothermal in the same sense. You’re talking about a heat pump that takes advantage of the difference in temperature at different depths in the Earth. In that case, you are the one who supplies the water, and yes the water will remain good-to-use if kept in an enclosed system.