Typical methods have been characterised of determination of the corrosion hazard caused by stray currents to metal structures transporting or storing aggressive media (e.g. fuel pipelines, tanks). Monitoring of the hazard allows determination of its extent, facilitates choice of the most appropriate anticorrosion protection method individually for each structure, and also enables evaluation of the effectiveness of a functioning protective installation. In the paper the practicability of the above mentioned methods has been assessed. Application of methods leading to erroneous conclusions regarding the corrosion hazard of electrolytic corrosion in relation to real electrode processes occurring on the metallic surface of the structure can lead to dangerous consequences. The effect of corrosion processes is the corrosive perforation of the metal leading to leakage to the ground of aggressive media contaminating the natural environment. Seeking of new unequivocal methods regarding electrolytic corrosion processes proceeding on structures is a fundamental issue.