Yes, I think you are right.
Back when I was working as a hydrogeologist, I worked with a consulting P.E., who had a side business drilling water wells. He dowsed wells (only when asked) and was 100% when he did this. He didn’t advertise being able to do this.
I watched him do it, and he could tell depth to water, thickness of the producing zone, and approximate the final well yield. This was proven time and again, as we completed each well. And it was not a geologically simple area: it was in an area of fractured granite bedrock, with faults; coarse alluvial fill; and buried blocks of faulted Paleozoic sedimentary deposits. In other words, a highly complex subsurface. As a hydrogeologist, I couldn’t believe it this, but I also could not argue the results I saw with my own eyes.
I have also seen plumbers do this sort of thing to locate water lines in a house with pipes under or in a concrete slab, in looking for leaks. (But they generally had to have flowing water to do this...)
Yeah, as a scientist I could not say I believed in it, but I also could not ignore the empirical evidence I saw with my own eyes. Kind of makes you think about things a bit...
I didn’t believe it either, until a friend of mine was asked
to find the water lines buried in the concrete floor of a
huge warehouse. He showed me how to hold the rods and then
told me to just randomly walk back and forth through the entire building. When the rods crossed he marked the spot.
I walked probably for a half an hour, never looking down, just at the far wall, then turning in another random direction and going off again. Finally, he said that’s enough and we stopped.
We started to connect the dots, and found the main line almost instantly. over ten dots in a perfectly straight line from the front to the back of the building.
It works.