Sewerin Variotec tracer gas being used to find water leaks in water pipes. The pipe is filled with tracer gas (hydrogen/Nitrogen mix). The gas escapes at the leakage point and is detected on the surface of the ground with a very sensitive gas detector, the Variotec 460. This technique is a well proven and very successful method of finding leaks in water pipes both outside and inside houses by plumbers and water network technicians