Electrical currents on metallic water service lines and mains affect corrosion of buried metal piping and can result in random shock hazards for water utility employees. The practice of using metallic water piping as part of the electrical grounding system of a building has been commonplace for more than 80 years. Modern electronics such as variable‐speed motors, televisions, and computers produce both direct current and alternating current (AC), which can flow along metallic water service piping. When electrical transformers serve multiple buildings, the water services and distribution piping can act as parallel neutral return paths for AC from building electrical systems to the transformers. AC can increase the rate of corrosion of distribution and service piping and create shock hazards for distribution workers. As long as the current remains on the electrically continuous pipe, corrosion is not affected. Corrosion occurs when current leaves the pipe and flows through the earth.