Hydrogen and water input in steel making processes are known risks in the iron and steel producing industry. In order to implement concepts for sensor-based monitoring, test measurements were carried out at the Chair for Process Engineering and Industrial Environmental Protection at the Montanuniversität Leoben as well as at the site of voestalpine Stahl Donawitz GmbH after basic research on various measuring principles. As the particle size of the input materials ranges from powdery to fist-sized granules, a variety of measurement principles was investigated, including the conductivity and capacitance measurement, the infrared reflection measurement as well as the analysis by microwave technology. The quality of the measured results depends very much on the respective measuring principles (contact measurement or electromagnetic measurement) as well as on the material to be examined. Contact measurement principles in the case of powdery materials merely provided rough estimates of moisture content. Contrary, large granular materials without pores can be analyzed satisfactorily with the infrared reflection method. Generally, for online measurements electromagnetic measuring methods show advantages compared to contact measurements.