The problems of detecting hidden subsurface non-metallic pipelines based on polyethylene, polystyrene polyvinyl chloride and polypropylene are considered. The electrical and magnetic parameters of the subsurface  medium mainly coincide with the parameters of liquids and materials of pipelines, which does not allow to detect them using conventional metal detectors. It is proposed to detect not the pipeline material itself, but rather its content.
A parametric method of detecting hidden subsurface non-metallic pipelines based on the parametric properties of liquids in pipelines, which are manifested during forced polarization of the liquid by turning the magnetic axes of the protons of the liquid to a certain angle relative to the Earth's magnetic field.  
The purpose of the study is to develop a new method of detecting hidden subsurface non-metallic pipelines, based on specifics of the parametric properties of the liquids transported by them.
The given parametric method has undergone experimental research and can be implemented in a serial sample of a means for detecting hidden subsurface non-metallic pipelines.