When my father had a well drilled it was recommend that a certain individual be hired to witch it as he "had the gift" and was never wrong in over 40 years of witching. He was hired, witched the area, marked the spot and said that they would hit good water within 35'. They drilled 105' and hit a mixture of salt and sulphur water with a sulphur content so strong the smell would gag you. They called him back he did it again, and this time they went down 100' and stopped. The rig operator guaranteed good water or you didn't have to pay so he figured he was not going to spend any more of his money drilling dry holes. A neighbor talking my father into blasting the 2nd well as all of our neighbors had good wells at 30' - 50'. The neighbor got his professional blasting friend who turned out to be an "amateur" (emphasis on the work amatuer) and he came in and blasted the well. The only thing he suceeded in doing was breaking my father's and his next door neighbors picture windows and cracking his foundation.
About 10 years later, city water was installed county wide.
The irony of the whole saga is that this property is in upstate NY about 500 yards from the banks of Lake Ontario. You can see the lake from the front porch. Not that I don't believe in dowsing but as they say, "your mileage may vary".
Injunbro - If you are using copper rods wouldn't the copper content of them overcome the mineral content of say a gold ring?
Don