This study focuses on the behavior of galvanized steel in a corrosive marine environment and on the runoff process for the same material occurring in Valparaiso, Chile. The corrosion potential and corrosion rate evaluated via mass loss were used to determine the corrosion damage to the galvanized steel. The compositions of the corrosion products were determined using X-ray diffractometry (XRD), and their morphology through scanning electron microscopy (SEM). The runoff solutions collected after rainfall were analyzed to determine the pH value, and Cl-, SO42- and Zn 2+ ion concentrations. The results after 15 months show that the corrosion potential of the galvanized steel increases over time, indicating the formation of a protective film that consists of zinc corrosion products. These products were identified as zincite and simonkolleite. The pH values obtained for the runoff solutions are similar to those of the reference rainwater samples, and the chloride concentrations of the runoff solutions are approximately twice those of the rainwater.