This article concerns the issue of the long-term operation of hydromechanical fittings during their contact with
aggressive water. The aim of this analysis was to investigate the significance of the quality of water during
the operation of wind power farms and geothermal power stations, especially hydromechanical fittings during
long-term operation at the base of the Baltic Sea and geothermal power stations. This article presents the
properties of water and their impact on hydromechanical equipment during long-term operation in marine and
geothermal waters. The paper includes the analysis and evaluation of their impact. Additionally, the article describes important problems with the operation of wind power farms and geothermal power stations. The results
of periodical analyses of southern Baltic marine water and thermal groundwater from “Geotermia Podhalańska” were evaluated and used as the basis for future research. Every negative parameter of water, known as its
aggressiveness, adversely affects the basic materials of wind masts and pipelines, as well as the hydromechanical equipment in contact with marine and thermal water. The presented results show the necessity of controlling
the water quality prior to the operation of geothermal water and building wind power masts in coastal marine
water. Attention was paid to corrosion during contact with aggressive water with unprotected materials. This
issue is rarely seen in the literature but is very important.