Prevent Natural Gas Leaks When Clearing Sewer Backups

What's underneath your feet: Cross bores

A network of power, natural gas, phone and cable lines, as well as water and sewer pipes may lie just under the surface of your property. In rare instances, a gas line is mistakenly installed within a sewer line, which is known as a cross bore.

If a cross bore is struck while a sewer backup is being cleared, it could cause natural gas to leak into your property or the sewer system, potentially leading to personal injury or an explosion.

In the United States, there have been cases of home explosions, fire, injury and death due to natural gas leaks from cross bores. While no instances have taken place in Canada, there have been cross bores detected in Ontario.

How cross bores occur

Trenchless or horizontal directional digging techniques are commonly used to install natural gas pipelines underground. These techniques have many benefits compared to open trench digging including being more cost effective, less disruptive than digging through streets and landscaping and having fewer environmental impacts. However, these methods don't enable construction crews to visually confirm where the new line has been placed, which may result in the line being installed within an older sewer line that is made of material that cannot be detected by utility locating technology.

Cross bores are not often the cause of a sewer backup but they can allow tree roots and other obstructions to penetrate sewer lines, which can lead to blockages.

Keep your property safe

Cross bores pose no safety threat unless they are struck by motorized or high pressure equipment, typically used by drain cleaning professionals to unclog a plugged sewer. This includes motorized augers, power-snakes or other root-cutting equipment.

What to do if you have a sewer backup

Call a drain cleaning professional and determine the source of the blockage.
Contact Ontario One Call if the blockage is determined to be outside your property and not from internal plumbing. Only blockages outside the property are at risk of cross bores.
Wait for Ontario One Call to confirm it's safe to proceed. They treat this as an emergency response and will visit your property to determine if a cross bore is present. This service is free of charge.

Prevent natural gas leaks when clearing sewer backups

What's underneath your feet: Cross bores

Stay safe

How cross bores occur

Keep your property safe

What to do if you have a sewer backup

Prevent natural gas leaks when clearing sewer backups

What's underneath your feet: Cross bores

Stay safe

How cross bores occur

​Keep your pro​​perty safe

What to do if you have a sewer backup

Keep your property safe