Sound sensors are placed in contact with the pipe, at two or more points, to record the sound emitted by a leak somewhere between the points. The sound data is processed through a mathematical algorithm which compares or correlates the two recordings to determine the difference in the times it takes noise to travel from the site of the leak to each of the sensors. If the distance between the sensors is known in advance, this timing information can be used to determine the location of the leak.Leak correlators require accurate information about the materials through which the leak sound is traveling in order to perform an accurate time calculation. Most leak correlators serve two major purposes. First is to detect the presence of a leak, second to pinpoint the location of the leak for repair when detected.