The town water department was out looking for a leak. They walked up and down, located everyone's shutoff valve, and left the street covered with blue graffiti, obscure symbology to locate stuff. Then they pulled out two or three fancy electronic instruments that made funny noises when they detected underground pipes.
After a lot of high tech stuff, one of the workers pulled a pair of dowsing rods off the truck and sure enough, the dowsing rods detected pipe about where the fancy instruments did. These guys clearly believed it worked. And they are not new age hippies, they are just plain middle aged working stiffs.
Told my daughter this story, and she came back with a long tale about how dowsing is a con game, and only the superstitious believe in it. That may be. There is certainly no explanation of how dowsing might work to be found in physics, geology, or chemistry. Be that as it may, the Franconia water department uses dowsing and believes in it. Long as they keep the water running to my place I ain't gonna say anything about their methods.