Smoke testing in plumbing, is used to test for leaking pipes in your facilities. Non-toxic smoke is used to find leaks in plumbing and sanitary sewer systems.
The test consists of blowing a harmless colored vapor into the sanitary manholes and observing the points where the smoke exits. The smoke is expected to exit from manholes, the sewer stack at the top of your house, catch basins and downspouts. Plumes of smoke form where there are defects.
It is particularly useful where completely sealing the system is not practical such as ventilated sanitary sewer systems.