I’ve run a public water supply company for almost 30 years. I’ve seen this work! 2 guys I know can do it. Not just for drilling wells, but for finding lost service lines.
Plumbers use it also to find pipes, I have never become convinced it works.
I’ve dowsed successfully. When I was 15 some heavy construction equipment rumbled through the side yard of our rural house and crushed the pipe from the house to the septic tank. We were newbies from the city. I was assigned the task of digging a trench the length of the house to find out where the pipe was.
I’d been reading about dowsing and I figured it couldn’t hurt to try it—I was going to have to dig a long trench and it didn’t matter where I started. I used clotheshanger wires bent into an L-shape and a couple of Coke bottles rather than brass cylinders. The wires kept swinging at the same spot as I paced along the side of the house.
I dug there and voila, the pipe was right there six feet down or so.
I worked for WSSC one summer and watched often as one guy on the truck would bring out his brass rods and find the water main. I never saw him miss.
Not everyone can do it, but some can.