Dowsing is odd.
Fifteen or so years ago I used to be quite keen on dowsing with rods. I found that I could detect close to surface anomalies with a reasonable degree of accuracy, being able to trace pipes amongst other things. However when it came to deeper stuff like mines or caves I had no luck.
One evening in the pub I tried an experiment involving half a dozen people, none of whom had dowsed before. I took each person (using my rods) through various rooms in the pub which could not be seen from the bar. Five out of the six people got a reaction from the rods in the same place. This, according to the landlady corresponded to a large water pipe entering the building.
I am convinced that dowsing works, but I am b*ggered if I know why. The most convincing hypothesis I have heard is that the arm muscles are picking up minute variations in magnetic field caused by an anomaly and twitch accordingly, the reaction being magnified by the rods. Then again it might all be just a load of mumbo jumbo and I might be a self delusional yoghurt weaver 😉.