A harmless white smoke is forced through the sealed sewer system. A sealed system means that there are very specific locations that the smoke should be able to exit the system. When a system is fully sealed the smoke will exit at these locations and nowhere else.
When smoke exits the system at locations OTHER THAN the identified locations it represents a crack, leak, or damage to the pipe system. Green Mountain Pipeline Services identifies the locations of the leaks, takes pictures, and logs the location so that repairs to the system can be completed at a later time.