Clearing Sewer Lines
Learn how utility lines can accidentally intersect sewer lines, why sewer blockages should be investigated carefully, and what steps to take if a cross bore is suspected.
A blocked sewer may be more than a plumbing issue.
A blocked sewer line may occasionally be caused by a utility line that was inadvertently installed through an existing sewer line, a condition known as a cross bore. While uncommon, attempting to clear a blockage without first identifying a cross bore can result in serious damage to underground utilities and may create a safety hazard.
Before using mechanical sewer cleaning equipment or high-pressure water jetting, it is important to determine whether a cross bore condition may exist.
What Is a Cross Bore?
A cross bore occurs when one underground utility line is unintentionally installed through another underground facility, such as a sewer line. If a sewer cleaning tool or water jet contacts the crossed utility line, it can damage the facility and potentially create a hazardous condition.
Before Clearing a Sewer Blockage
If you are unable to visually confirm that a cross bore does not exist, request an emergency utility locate through Dig Safe at 811. If utility markings cross the known path of the sewer line, a cross bore may be present and additional investigation is required.
If You Suspect a Cross Bore
Do not attempt to clear the blockage using:
- Mechanical sewer cleaning equipment
- Sewer augers
- High-pressure water jetting equipment
Instead, contact the affected utility operator for assistance. Vermont Gas can be reached at (800) 639-8081.
If You Suspect a Natural Gas Leak
If a natural gas leak is suspected:
- Leave the area immediately.
- Instruct others to leave the area.
- Call 911.
- Contact Vermont Gas at (800) 639-8081.
- Do not operate equipment or create ignition sources.