Blocked sewer or septic? It could be cross boring.
What is cross boring and could this be the cause of your sewer or septic pipe blockage?
Cross boring is a rare situation where a natural gas line has been inadvertently installed through a sewer or septic pipe. If the sewer or septic pipe becomes clogged, your efforts to clear it can damage the intersecting natural gas line and allow natural gas to escape.
What if the blockage is inside the building?
If the blockage is inside the building, the clog is not a natural gas system issue and it is ok to clear the blockage. If it is determined the blockage is outside the building, this could be a potential cross boring issue.
Your plumber can help
Your plumber or drain-cleaning professional may recommend inserting a camera in your sewer or septic pipe to look for the obstruction. This is a good practice, and will help identify the blockage. Contact the natural gas company in your area if you are unsure if the obstruction is a natural gas line.
When is there potential risk of a cross bore?
When installing a new natural gas line, it is not uncommon for the natural gas company to dig horizontally underground (called directional boring). This method does not involve digging a trench, thereby avoiding damage to roads, driveways, sidewalks, patios, landscaping, and other existing utility lines (electric, communication) which are marked after placing a one-call notification to 811. Because there is not an open trench, it is possible the underground boring could pass through another underground utility line.
If a cross bore is discovered
- Stop all work
- Contact SCG at 800.513.8898
- If you suspect a natural gas leak by smelling, seeing or hearing natural gas escaping inside or outside:
- Leave and instruct others to leave the area immediately
- Call 911 after you exit the building and from a safe distance away from the area
- Keep others at a safe distance
- Do not operate any equipment
- Eliminate any source of ignition
- Do not operate any pipeline equipment
- Proceed with your work ONLY after the area is made safe by first responders and the local natural gas company
View cross boring videos from the Gas Technology Institute:
Plumbers and Contractors Video