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Smoke Testing


Smoke coming out of a catch basin while smoke testing is done in the area.The City of London periodically conducts sewer smoke testing to assist staff in identifying areas that need improvement within the sewer system.  Smoke testing is a safe, relatively inexpensive, quick way to find areas of the sewer system that need updating.  

Preparing for Smoke Testing

When your receive a notice that smoke testing will take place in your area, you should check to see that all traps under basins, washing facilities, and floor drains have water in them.  This will eliminate some points of entry of smoke into your home.

Is Smoke Testing Safe?

The smoke used in the test has no odour, isn’t harmful to your health, and will disappear in a few minutes.  The test consists of blowing a harmless coloured vapour into the sanitary maintenance holes and observing the points where the smoke exits.  The smoke is expected to exit from maintenance holes, the sewer stack at the top of your house, catch basins, and downspouts.  If the smoke does enter your home, it may make you cough, but it is not harmful to your health and will not harm clothing, drapes, or furniture.  The smoke is not harmful to pets.  It would be a good idea to leave several upstairs windows partially open for ventilation, should any smoke enter the building.  If you have proper plumping connections and all of the traps have water in them, there should not be any problems.

Smoke coming out of a home when smoke testing was done in the area.If Smoke Enters My Home…

If smoke enters your home note the location of the smoke and contact the Field Supervisor at the number provided on your notice or contact the City of London at the number to the right.  City staff will explain what should be done to correct the problem.
The main purpose of the testing is to find potential points of “inflow and infiltration” of storm water into the sanitary sewer.  Smoke testing can help locate improper connections to the systems and areas where unwanted water is entering the system.  If a problem is found, the City of London will take steps to make the necessary improvements.

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