I have a smaller 22 pads park in central Georgia that was built in the 1950s. The park has old galvanized pipe ‘buried’ maybe a few inches deep. How crazy would I be to pick up a metal detector for mapping these lines? Sounds like a creative/cheaper initial solution, but I’ve never used a metal detector and don’t know what to expect.
Water lines can be very shallow when there’s no real frost line to worry about.
That would be amazing if you can do that. You could use your detector and map the lines and mark them as you go. Use a probe rod to confirm the pipe is there. At the end, you could overfly a drone and take an aerial map. That would be a simple and cheap way to do it if it works, however, I don’t know if it would work. In my area, water lines are buried quite deep.
I do landscape irrigation and have located many water lines using a metal detector. You can rent them and they are not difficult to use. Suggest you use noise-cancelling headphones vs. the speaker on the detector.
A metal detector might help. I have found that it also has you look for every nail or screw in the ground.
Usually, all of the pipe will be in a straight line. Use the risers as a guide and visualize were the pipes are. You can confirm it by digging the few inches to find the pipe.
You can dial 811 on your cell phone and have the power company, water, gas,electric, satelite, cable service person come to your property and mark the lines, poles, underground cables. They flag them with difference colored flags to help you identify. This service is also FREE! I don’t know if you have this available in your area, but here in south Alabama we do. Won’t hurt to give it a try and see. Best of luck to you!