Cross Bores

When a utility line is installed inadvertently through a sewer line, it is commonly referred to as a cross bore. Unless the utility line is damaged, cross bores do not pose a safety risk.

Many utilities use “trenchless technology” during construction to install underground lines. This technology allows underground lines to be installed while avoiding damage to streets, sidewalks, driveways and landscapes.

An illustration of a cross bore - with a natural gas line going through a sewer pipe.With trenchless digging, sometimes an underground utility line can inadvertently be installed through an existing utility underground structure such as a sewer line.

These cross bores can go unnoticed for months or years, while the gas or other utility line is obstructing the flow of waste in the sewer pipe.

Eventually, however, a cross bore can lead to a blockage or backup.

Be Alert For Cross Bores In Sewer Lines

Plumbers, sewer cleaners and drain cleaners should always assume any obstruction in a sewer line is a cross bore and take special precautions before performing any sewer line cleaning or maintenance.

Otherwise a cut, nicked or dented natural gas line or other utility line can create a safety hazard.

Be Safe

  • Call 811 before you or your contractor clear any sewage blockage.
  • Assume all obstructions involve a cross bore.
  • If you suspect a gas line blockage of a sewer line, please call Eversource at 800-592-2000.

More information about cross bores and cross bore safety is available in our brochure.