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Sarnia using smoke to test for leaking sanitary sewers

Published on

Troy Shantz

City hall has been blowing a lot of smoke lately.

The smoke is used to test for leaks in sewer pipes in the Coronation Park area, which official hope can provide insight into flooding that’s plagued the neighbourhood.

“It’s pretty clear that whenever we get a rainstorm a significant amount of rainwater is getting into the sanitary sewer, which it shouldn’t be,” said city engineer David Jackson.

“Smoke testing is a good tool and part of our investigation we can take to try and determine where it may be coming in.”

The process used by Wessuc Inc. involves pumping non-toxic smoke into sanitary sewer lines with a high-pressure blower.

Smoke indicates a leak. Residents were advised to watch for smoke wafting from sinks, sewer drains, gutters and downspouts, as well as along the ground near sewer lines and catch basins.

The grey smoke has a slight odour but is harmless to people, plants and animals, city staff said.

Last summer, a group of homeowners said Sarnia bears some responsibility for the ongoing problem of basement flooding in Coronation Park, which includes Buckingham Road, Tunis Avenue, Tweedsmuir Avenue, Mayfair Drive and Minto Street.

“I think (smoke testing) is probably a necessary step to fixing the problem,” said Darcy Colborne, a Minto Street resident who has spent thousands of dollars trying to stop flooding in her basement.

“It depends on what they do with the results. My question is what’s next?”

Minto and Tunis meet in a quiet neighbourhood lined with 1950s-era homes east of Germain Park.

After Colborne filed an insurance claim for a flooded basement in 2019 she had a backflow valve installed. But when water again surged from the sewer drain last August it destroyed the backflow valve and entered her basement yet again.

Colborne, a construction estimator by trade, said many of her neighbours have also spent thousands of dollars unsuccessfully trying to fix the problem.

If smoke or odour appears from indoor plumbing and drains within the test area it indicates dangerous sanitary sewer gases may be entering the house. That shouldn’t happen if the plumbing is in good working order, the city said.

David Jackson said some homes built before 1985 had rainwater drainage systems connected to the sanitary sewers, and that could be part of the flooding problem.

“For example, we may see (smoke) coming out of a house by the eavestrough. If their eavestrough and their downspout connect into the ground and into the sanitary sewer line, then that means that the rainwater from the roof is getting into the sanitary sewer.”


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