Strange you bring that up. The douser (my Uncle insisted I get one) used two copper rods, 3/8" diameter and 20" long, bent in the shape of an "L". This guy did dousing for a local town who hit three for three wells pumping 100 or more gallons per minute.
He walked all over the property marking where underground water was flowing. One of the spots (the one that hit) was directly under a 220 VAC 60 Amp service feeding our pole barn. This is the spot I wanted but a Blue Spruce tree and overhead lines were in the way. The tree is gone, the lines have to be re-strung, and the water will be flowing very soon (we hope).
Me, being more of a logical thinker thought it was strange that these copper rods could be sensitive to water +50 feet down or deeper and yet not be influenced by overhead power lines 15' away.
I gambled to family pressure and lost.