Growing up, everyone in the area had their water wells dowsed, usually by an old fella named Keith. No one questioned the practice. I have no idea how accurate he was.
When my dad and I were building my little cabin in my grandmother's backyard we were required to call the locator guy before digging, but dad dowsed for buried lines and objects first. The locator guy found a natural gas line and a sewer line and marked them. Dad had found those, but also two other lines and something that seemed to be a large buried object that the official locator guy didn't pick up. As we dug, we were mindful of both the official markers and dad's markers. We soon found an old abandoned sewer line, parallel to the new one but 5 feet east, and an abandoned and rusted out fuel oil tank. More disturbingly, we found something that looked like a very old natural gas line. We called the gas company and they said, Oh yeah, there's an old network of gas lines that we haven't used for 10 years, but we haven't quite gotten around to capping and draining. Yup, dad found a live gas line that the locator dude missed.
I was curious and gave dowsing a try. Only my left hand works - I always put a bent wire in my right hand too and it waves around at random, but indicates nothing. My left hand is pretty accurate though, and only works if I also have a wire in my otherwise useless right hand. I have multiple sclerosis, so I wonder if that has an effect. I'm accurate to within half a foot or so for buried lines, and I can choose what I'm searching for - only sewer, only water, only fiber optic, etc. My dad is astonishingly accurate, to the inch, but finds everything and can't tune anything out. He's really good at finding gold - likes to pan for gold and can find concentrations with his dowsing rods. He has been told that he probably has MS as well, and if he's tired or chilled he can't dowse anything.
