Because of PE's material makeup, it is not locatable using detection systems common to metallic piping material. Therefore, detection systems require installing a tracer wire or plastic coated metallic tape in the trench during PE pipe installation. Inductive electronic pipe tracer systems are available that inductively detect the metallic tracer wire or plastic coated metallic tape from the surface. Detection of pipelines at greater depths can be successfully achieved through conductive detection where the detector is physically connected to the tracer wire or tape. Acoustic sounding devices can also be used.
Ref: Christensen, Melissa, ed., PE Pipe-Design and Installation, Manual of Water Supply Practices M 55 (Denver, CO: AWWA, 2006)