Answer:
Due to different mineral deposits, groundwater may contain different minerals. I think it was in California, not 100% sure, but there was silver in the water a long time ago and now there are veins of silver everywhere.
Places that have lots of calcium and zinc in the ground may create hard water (water that has lots of minerals in it).
Hard water is a problem in many places because it clogs pipes and taps. You may see in your house if you look into the faucet, there can be white buildup. That is minerals from hard water.
Hope that helps