Sanitary Sewer Smoke Testing

The City of London has begun conducting sanitary sewer smoke testing to assist staff in identifying areas that need improvement within the sewer system.

What is Smoke Testing?

Smoke testing is a safe, quick way to find areas of the sewer system that need updating. 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.

The smoke should not enter your home if it is properly plumbed and if your sink and drain traps contain water. 

Frequently Asked Questions

What is the purpose of smoke testing?

The purpose of the testing is to find potential points of "inflow and infiltration" of storm water into the sanitary sewer. Smoke testing an 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.

What are the benefits of smoke testing?

Smoke testing is a simple and fast method of testing the sewer system. The vapour is harmless and will disappear after only a few minutes. The testing is also an inexpensive way to find areas of the sewer system that need improvement. 

Is the smoke harmful?

No. If the smoke enters your home, it may make you cough, but it is not harmful to your health and will not harm clothing, drapes, or furniture. 

What should I do to prepare for the smoke testing?

When you receive a notice that smoke testing will take place, you should check to see that all traps under basins, washing facilities, and floor drains have water in them. 

What does it mean if smoke enters my house?

If smoke does enter your home note the location of the smoke and contact the Field Supervisor with the smoke testing crew at 519-429-9148 or contact the City of London at the number below. City staff will explain what should be done to correct the problem.

I will not be home during the testing and have pets. Should I be concerned?

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 plumbing connections and all of the traps have water in them, there should not be any problems.

Contact Information

For more information or to report the presence of smoke within your house during testing, please call the City of London Wastewater & Drainage Engineering Division. The City's project manager, Ashley Rammeloo, can be reached at 519 661-2500 ext. 4993.