How to Locate the Underground Cast Iron Pipes
- 1). Buy or rent a metal detector and familiarize yourself with the documentation that accompanies all new metal detectors. Read the documentation on the manufacturer's website if you buy a used metal detector. Buy or rent a metal detector that allows you to evaluate whether buried objects are ferrous or non-ferrous.
- 2). Determine, if possible, one end and the course of the underground cast iron pipe you seek. Begin your investigation there.
- 3). Activate your metal detector and switch on the setting that allows the detector to ignore non-ferrous metal objects.
- 4). Hold the disk-shaped detector coil just above the surface of the ground and slowly sweep the metal detector back and forth, like a broom, while you hunt for the underground, cast iron pipe. Search the area where you think the pipe is most likely to be buried first.
- 5). Mark the straight line that contains buried iron or steel with surveyor's stakes.
- 6). Confirm the location of the cast iron pipe by digging a trench under the line described by the stakes.
Source...