Learn about our approach to pipeline replacement and view active and completed projects.

Sometimes natural gas pipelines need to be replaced to meet expanding customer and/or natural gas system needs as well as to accommodate infrastructure improvement projects of cities, counties and state agencies.

How it Works

A pipeline replacement project can be a significant construction operation. Typically, the new pipeline segment is installed adjacent to the existing pipeline, which allows the construction work to proceed without stopping the flow of natural gas through the original pipeline. Here's how it works:

  1. A trench is carefully excavated alongside the path of the original pipeline into which the replacement pipeline will be laid. New pipeline is made of steel and comes with a coating on the outside that prevents moisture from coming into direct contact with the steel and causing corrosion.
  2. The new replacement pipeline sections, usually 40- to 60-feet long, are carefully welded together to create a continuous length of pipeline that is lowered into the trench using cranes.
  3. Before being placed into service to carry natural gas, the interior of the replacement pipeline segment is thoroughly cleaned to remove any dirt or construction debris.
  4. Finally, it's given a safety check with a hydrostatic pressure test which pumps water into the pipeline segment and pressurizes it to a level well above which it will operate. If the pressure test reveals no leaks, the pipeline is ready for use.

The natural gas remaining in the existing pipeline segment is safely vented and it is disconnected from the main pipeline. Next, the replacement section is connected to the main pipeline and it is safely brought into service.

Minimizing Impact to the Community

Whenever SoCalGas® installs a replacement pipeline in a community, we make every effort to minimize and mitigate any impacts. If a pipe replacement is happening in your community, you may see trucks and equipment on the streets, excavation sites, temporary “No Parking” signs on streets, possible lane reductions or closures, detours and temporary delays on surface streets.

Community members may hear some work-related noise and notice an occasional natural gas odor. We strive to provide continuous natural gas service for our customers throughout the replacement project process, but in some instances there may be temporary natural gas service interruptions.

SoCalGas appreciates the cooperation and patience of our customers and the communities we serve as we work to enhance the safety of our natural gas pipeline system.

How Long Does it Take

It may take several weeks to install a replacement pipeline, and the duration varies depending on a number of factors such as the length of the process for obtaining necessary permits, permissible working hours as determined by the local jurisdiction, traffic control issues, length of pipeline being replaced, location of the pipeline, ease of access to the pipeline, amount of excavation necessary to install the replacement pipeline and even the weather.

When the pipeline replacement is complete, the excavated areas are “back-filled” by returning the removed soil into the trench, and later graded and restored as closely as possible to their pre-construction condition. Any needed street or property repairs are also made.