It's one of those things that believers believe in no matter what. Just like homeopathy. If you believe then there is no level of contradictory evidence to dissuade you. It's worked for you so it's true. Irrespective if whether there's identified reasons why it appears to work for ppl.
Still it's harmless for individuals to do it. I just object when it's got a cost (however small) to be through utility bills. I would rather the water utilities kept better plans of where their pipes were in the first place. Or just stick to proven methods.
I'm always an uber-sceptic of this sort of stuff. However, there does seem to be at least some anecdotal evidence that it can work so maybe it's worth thinking about a possible mechanism for how it might work?
I am struggling to imagine a mechanism whereby the water directly affects the rods. But it sounds like what is happening is some connection between the water and the muscles controlling the rods. So what could that be?
How about, we actually have some deep-seated hydrological sense in the same way some animals do with regard to underground water. That may be smell, sonar, whatever...I don't know. Those who are "sensitive" to this and actually "want" there to be a mechanism are subconsciously connecting their deep-seated hydrological sense to their muscles
I'm off into the garden with my coathangers now