Smoke Testing


The test consists of blowing highly visible non-toxic “smoke” into the sanitary sewer system at manholes and observing the locations where the smoke exits to the surface (manholes, catch basins, roof top plumbing vents, connected downspouts, driveway drains etc). The “smoke” that is used is manufactured for this purpose. It is non-toxic, odourless, non-staining (on clothing, draperies or furniture) and has no known effects on people or pets. If you come into contact with the “smoke” it is not harmful to your health and will dissipate shortly after test completion.

The fire department will be notified during testing. Please do not be concerned if you see smoke coming out of your rooftop vents or street manholes. This is normal.

During the testing, TQI staff will be on-site to observe & record smoke exit points. TQI staff will be wearing identification badges, orange safety vests and will not need to enter onto your property.It is not necessary for you to be home during the test, as the primary concern is external deficiencies.

Smoke should not enter your building, unless you have:

To help prevent “smoke” unnecessarily entering your building, the City asks you to pour a litre of water into your basement floor drains and unused showers, sinks and piping rough-ins PRIOR to the start of testing on June 22nd. The water added to the drains / traps will be effective for several months.


The purpose of this testing is to find locations where rainwater is entering the sanitary sewer system from cross connections and other infrastructure. If a source is found, steps can be planned to correct it.

"Smoke" testing is a cost effective and quick method of testing connectivity to the sewer system and locating potential improvements. The "smoke" vapour is harmless and will disappear after a short period of time.

When you receive notice that smoke testing will take place, you should ensure that all traps under your sinks, floor drains and any plumbing rough-ins have water in them by pouring a litre of water down these drains. This water will be effective for months.

If smoke enters your home during the test, there are deficiencies in the building's internal plumbing (ie, a dry trap or lack of a trap) within the house that allows the testing smoke vapour and any potential sewer gas to enter.

If "smoke" does enter your home and causes you concern, note the location of the smoke and contact staff listed on this notice or on our Project Website at to help explain the situation.

If any of the harmless "smoke" does get into your home, simply open a few windows for ventilation. The smoke" will disappear shortly after test completion.

The "smoke" is not harmful to people or pets. However, it would be a good idea to leave an upstairs window partially open for ventilation, should any smoke happen to enter your home during the testing process.