I was always skeptical of water-witching although many folks I knew claimed it worked. In the early ‘80s I was a site superintendent of townhouse and apartment projects in Vancouver, B.C.
One fine day, after preparing an underground parking lot for paving, it was discovered that the drainage contractor had not mapped the clean-outs or runs of sub-surface drainage tiles.
Short of recruiting a dozen laborers with shovels, I was at a loss as to how to map and flag the pipes. One of my plumbing contractor’s men suggested witching; I laughed but gave it a try with two bent steel form-ties. It was uncannily precise and effective, even if inexplicable.
I’ve never had cause to try the technique again, but am no longer a “denier”. ;^).
Wouldn’t it be refreshing if people spent more time trying to figure out why it works for some people than conducting studies that say it doesn’t work?