A magic pipe is a surreptitious change to a ship's oily water separator, or other waste-handing equipment, which allows waste liquids to be discharged in contravention of maritime pollution regulations. The pipe may be improvised, aboard ship, from available hoses and pumps, to discharge untreated waste water directly into the sea. As ships are often required to keep records of waste and its treatment, magic pipe cases often involve falsification of these records too