A model that can be used in determining the efficiency of an anodic protection for equipment, which depends on the various physicochemical parameters of the medium, has been developed. A series of model calculations were carried out for the following system: the anode (zinc and an alloy based on aluminum)-steel (St 3) in two media: chemically treated water and the rinsing water of the ionite filters. Data on the effect of the electric conductivity of the medium on the radius of the protected zone was obtained. All calculations were based on the kinetic and thermodynamic parameters of processes at the electrodes in the media under investigation.