I am having a tough time tracking down my underground drain system that the builder put in 15 years ago for my homes gutters / sump pump. I found all drains except for the final drain pipe that goes into my seepage "dry" bed. I have already run an expensive rental drain camera and a cheap one I bought on Amazon and don't see the opening but I know it's there because in the air vent opening in seepage bed I can "barely hear" the water going into the bed. I have found a place that rents this device to find leaks: LD-12 Sonic Subsurface Water Leak Detector. I would run water into the drain system. Then I was hoping to listen to the ground. Most of the pipes that I have found are between 2 and 3 feet deep covered by clay soil. I would make sure the soil was dry and then run my experiment. Any ideas if this might work?