re: #37 Anymouse 🌹

WTF? When I need to find a water pipe (being the town water operator), I use a metal detector or the town maps of our water system.

I used to mark underground conduits. We used a transmitter to inject a RF signal onto a specific metal pipe/cable and used a receiver wand to follow the signal. The wand would tell you if the conduit was left, right, or directly under. Science, it works.