I described the real space observation of H-bond dynamics within water-based model systems assembled on a metal surface. Low-temperature scanning tunneling microscope was employed to image, assemble and characterize such systems at the single molecule level. The combination of manipulation and controlled dissociation of individual water molecules made it possible to construct a variety of H-bonded systems. In addition to the assembly of desirable model systems, the time-resolved measurement of STM was proven to be useful to unveil the process of H-bond dynamics at the single molecule level. The voltage and current dependence of a motion or a reaction provided the key to elucidate the elementary processes. Especially, the voltage dependence is directly associated with vibrational excitations of molecule and quite useful for chemical identifications of adsorbates as well as for determining dynamical properties.