Most lines are located along the sides of streets and roads, or in the medians of city streets. Only some are marked. While the company knows about where they all are precise locations using the latest technology is a key to safety.
Ivan Altamura is the Director of the utility company's Pipeline Pathways program.
"In knowing exactly where the lines are that will help us in our gas patrols leak surveys with first responders."
This statewide pipeline safety effort is a result of the massive natural gas pipeline explosion in San Bruno two years ago. In addition to identifying the locations, PG&E plans to clear the right of way above the lines. That means trees, and structures over the underground lines could be removed. Most noticeably in the city of Fresno's median islands. Fresno Public Works Director Patrick Wiemiller does not expect a significant impact.
"They do have to do some removal of some trees and bushes in certain places where it's becoming a conflict with their infrastructure but the good thing is in cases where that is happening they are replacing on a two to one basis so if they remove a tree we will be getting two in its place."
New trees will be located a safe distance from the pipeline, or in other locations around the city. PG&E has so far identified 1,400 trees or shrubs that could be removed or replanted.
In one area near Belmont and Marks the gas line runs right through a row of trees in front of a house. The property owner says they haven't heard from PG&E but the company says property owners will be compensated for any landscaping or structures that have to be removed or relocated.
In the few places where fences or sheds cross property lines PG&E will work with the property owners, even if they have encroached on the company's right of way.
PG&E is in the process of notifying property owners and the public about the work.