IF you have a well it will be ok, because that water is natural, but test anyway, you can also buythings like stress coat that neutralize heavymetals, and chlorine
NOT ALWAYS TRUE...well water that goes to more that a certain number of people IS TREATED! If it's on your personal land, then you would know, if it the well goes to the whole block or an area of people, chances are it's treated. Smell the water, does it smell like rotten eggs? If not, then it's treated.
(Dad's a water person, does water for a living.)
Have your tap or well water treated for everything, then you'll know if it's safe, but even so, what about things we can't test for?