Cross boring safety

What to do when sewage pipes and natural gas lines intersect

Traditional digging techniques can be disruptive, and we try to avoid that. That’s why we often install new pipe by boring underground rather than digging trenches.

On rare occasions, when boring, something called a “crossbore” happens. This is when a new natural gas pipeline is accidentally installed through an existing sewer or septic line. Crossbores become a safety concern if the natural gas pipeline is damaged, since the sewer or septic line provides a pathway for natural gas to enter buildings.

Pipeline damage at crossbores typically only occurs when there’s blockage in a sewage pipe and cutting tools are used to remove the blockage. Fortunately, you can avoid damaging a natural gas pipeline by following a few simple steps.

Steps for plumbers


  • Call 811 to have underground utility lines marked.  If the location of the blockage is near the crossing of a located gas pipeline, then be aware that a crossbore may have occurred.
  • Look for signs of recent utility work being performed in the area.
  • Check for signs that a natural gas line is nearby, such as a pipeline marker.


  • Always use an in-line camera to identify the blockage prior to beginning any clearing activities.
  • Instead of a cutting tool, use a snake or water jet to clear the blockage.
  • Feel for obstructions that are different than roots or other common obstructions.


  • If a cutting tool was used, check the blades for yellow, orange or black plastic.
  • Look for bubbles or a rotten-egg smell. This means gas is leaking.
  • Inspect the area with a gas-detection device.


Steps for homeowners

  • If you are performing the plumbing work yourself, always call 811 to have your utility lines marked before beginning work.
  • If the plumbing work is being performed by a contractor, always ensure that they have called 811 to have utility lines marked.
  • Let your plumber know if any utility work has recently been done in the area
  • Ask that your plumber use an in-line camera to identify the blockage prior to beginning any clearing activities.
  • Request the use of a snake or water jet instead of a cutting tool to open the blockage.
  • After the project is completed, make sure there’s no rotten-egg-like odor near the site or coming from the home’s sewer orseptic drains.


Steps to take in case of a leak

  • Before you do anything else, leave the area.
  • While leaving, don’t turn any electronics on or off (including your phone), and never ignite a flame near the leak.
  • Call 911 and Spire’s 24/7 emergency line. [Website copy will link to our contact us page. Printed copy will list regional contact info]
  • If you don’t own the property, notify the owner.
  • Stay clear of the area until you’re told by Spire or emergency personnel that it’s safe to return.