Metal wire ones rom the dry cleaners can be turned into dowsing rods. You need two coathangers and two biro outers ( without the refills) and a pair of strong metal snips.
You cut the hangers with metal snips, at one side of the horizontal bit and beside the hook on the other side, so that when the short leg is straightened out you have L shaped wires. Put the short wire legs of the two Ls into the end of the biro cases, cutting them shorter if they are too long, so that you can hold the biro cases with the long legs of the wire swinging loose.
Then you hold one biro case in each hand, out in front of you, with the wires pointing very slightly downhill. They will swing wildly about until you get them balanced. Walk slowly forward over the area you want to dowse and note where they swing together for no obvious reason. This has worked for me both outdoors over a water supply pipe and indoors over a conduit carrying elecric cables across under the floor.
Entertains children (and adults) at no cost. Have fun.