You will see smoke rising from the outside vents of the residences and businesses during this test which is a sign that the plumbing is vented properly. If you experience smoke inside of your residence or building, it could be a sign of faulty plumbing, improper connections or dry traps on your plumbing. The smoke is harmless and non-staining and will exit quickly by opening a window or ventilating your building. If you experience smoke indoors coming from under sinks or any fixtures you need to contact a plumber to check your plumbing for the above mentioned problems. Faulty plumbing is a sign that sewer gases could be entering the building which can be harmful to your health when not corrected. The City is also conducting this test to locate leaks to the system to be repaired which will reduce operating costs to the system. Thank you for your cooperation during this test.