US Patent 7616119 Method of locating pipelines using RFID technology

A system is shown for locating hidden pipelines, particularly underground pipe used in a plastic pipeline such as for municipal water and sewer applications. An RFID tag is associated with the pipeline prior to installation of the pipeline into the ground. This can be done by associating the RFID tag with a sealing gasket which is subsequently installed at a sealing joint location of the pipeline. The tag can also be associated with the pipeline itself by installing the tag on a section of pipe. The location of the subsequently buried pipeline can be determined by interrogating the RFID tag with a suitable reader, the reader being located at an above ground location.