We have succeeded in applying laser-induced shockwave plasma spectroscopy (LISPS) to the problem of the detection and analysis of metal elements deposited from water samples by means of electrolysis. It is shown that metal elements are generally deposited in the form of a thin film on the electrode surface, while the electrode also conveniently serves as a subtarget for the relatively soft metal film, thereby providing the necessary conditions for the generation of shockwave plasma, which is favorable for highly sensitive spectrochemical analysis. It is shown that the detection sensitivity of this method reaches its highest value at low surrounding air pressure of around 1 torr. The lowest detection limit attained for various metal elements investigated in this experiment varies from around ten to a few tens of ppb. This limit can be readily improved upon by incorporating an optical multichannel analyzer into the detection system. We have thus presented a promising method for the realization of a compact mobile monitoring system for the accurate control of water and soil quality.