In the article are examined basic laws governing the flow of corrosion on the line of watershed (water line) in the zone of drops and the connection of this process with the potential of sinking (by potential Of [billitera]). Is proposed the electrochemical model of corrosive process on the water line, which makes it possible to explain the form of corrosive curve. The increased attention is given to the calculated of the speed of corrosion according to the water line in the zone of drops of power machinery equipment.