Cross Bore

Sewer Line Blockage: Protecting yourself and others from danger

If a gas or electric utility is inadvertently installed through a sewer line, a potentially hazardous situation exists. This intersection, known as a cross bore, can compromise the integrity of underground utility structures.

An undetected cross bore could result in a sewer backup. Clearing a cross bore may puncture the utility line and result in a catastrophic explosion or electrocution, severely threatening the safety of contractors and the general public.

How does a cross bore occur?

Trenchless drilling is a method that many utilities use to install underground facilities with minimal damage to landscaping, streets, sidewalks, etc. If sewer lines are not marked, there is a potential to drill through it, resulting in a cross bore. Although this type of damage is usually identified quickly through the use of post-construction cameras, it may also go undetected for months or even years.

Safety precautions

Before attempting to clear a sewer backup, consider the risks of a cross bore:

  • Call Diggers Hotline (811) to identify the location of sewer facilities and look for a utility conflict.
  • Check whether there were any recent excavations in the area to install or upgrade utility lines.
  • Plumbers/contractors should use a camera to identify the location of the blockage and condition of the lateral.
  • Be aware of any unusual conditions including:
    • Hissing noises
    • Natural gas odor
    • Blowing dirt
    • Bubbling water

If you suspect a cross bore, DO NOT attempt to unclog the sewer pipe. This could penetrate a utility pipe resulting in a natural gas explosion or electrocution. Instead, call MGE's emergency response line at (608) 252-1111 or toll-free 1-800-245-1123.

If you suspect a gas leak or contact with a natural gas line has occurred

  • Evacuate the area immediately.
  • Do not touch anything that might create a spark (light switch, telephone, cell phone, garage opener, etc.).
  • Call 911 from a safe distance.
  • Call MGE's emergency response line.

Safety commitment

MGE is committed to controlling emergencies where natural gas may be involved. Our crews are trained to handle any situation that may involve natural gas and should be notified immediately about any hazardous situation. We also work with emergency responders and state and local agencies to prevent and prepare for emergencies. If you would like to learn more about the potential dangers of a cross bore or would like MGE to provide training, please call us at (608) 252-7222.

If you suspect a gas leak, call 911 and our emergency phone line, available 24-hours per day, at (608) 252-1111 or toll-free 1-800-245-1123.