Well, lol, I had a well digger (driller) out to my place three years ago and I was amazed at the demonstration of witching. Those rods would cross like you would not believe. The well person (politically correct?) would have me come stand in a spot, then the well person would begin walking in another direction. I would be asked to place a stick where I was standing and to come stand where the well person now stood. This went on for several minutes, me placing a stick where I stood then going and standing where the well person stood placing another stick etc. THEN! All of a sudden the well person said, "There is a vein right here. Bring me a stick." Vein? I wish I had taken motion pictures of this!
I delayed the drilling of the well (money). Three years later the same well person came to my property. My house was framed in so it was time to think about a well. For three years I have hauled water in though I do have a spring fed pond. I never got ambitious enough to boil that pond water for drinking. This time I asked if the spot located three years earlier was absolutely necessary or if maybe the well could be drilled in an alternate location I had determined to be more practical for the location of the house. Once again the same ritual, witching for water! "There is a vein right here. Bring me a stick." Again I wished I had taken moving pictures, again I did not think about doing so. The process of witching is not something people see everyday. I doubt youngsters growing up in the big cities will ever see it unless someone programs a video game that includes witching, maybe some Harry Potter weirdness or such.
The well was not cheap. We had a "big hole" well drilled ( yes a drilling rig) that was lined with 30" concrete tiles. At 45' the well person stopped and showed me water squirting out the side of the hole that looked to be about the diameter of a pencil. The well person said that was enough water to water 100 head of cattle each day! I thought , wow, are we gonna stop there, it sounded good to me. But no, the well person said he was still in sand ( obviously he was in sand from the looks of the pile of sand out of the hole) and wanted to go deeper because the well person knew there was clay down there somewhere. The clay would prove to be more stable for supporting the tiles as it was explained to me. So 33 feet later we had the bottom of the well! 78 feet of concrete tiles with the outside of the tiles lined with pea gravel in order to keep sand filtered out. It was not "cheap" but I feel good about long term water supply. I have had friends come to my place that have lived in the area all their lives ( I am a newbie trying to get the heck off the grid!) telling me the water is "spring water". It does taste good, no iron taste and most importantly no chlorine, gag, taste like big city water. I don't care about the lack of fluoride "scare" we hear about these days for I have already lost a good number of my natural teeth and I have drank fluoride treated water for many years in the big city.
Just my experience with a "witcher" . I had a blast with it though in my area I think one would find water anywhere. Funny sometimes deep wells don't do the trick so people have to go back to the old way, big hole wells.