SALINAS, Calif. -

Pacific Gas & Electric gave News Channel 5 a bird's eye view to monitor an underground operation.

"We're patrolling about 11,000 miles a month," said David Wood, PG&E's pipeline patrol superintendent.

PG&E increased these federally-required patrols drastically over the last four years, since the deadly San Bruno explosion in 2010, as part of their leak-detection strategy. That includes about six or so other safety measures for anyone working on gas pipelines.

On the Central Coast, PG&E is in the process of hydro-testing the natural gas in its pipeline system.

"They take the gas all out and then they fill it with water and then they pressurize it to take it up to a maximum pressure," said Wood.

A station near the Monterey Peninsula is then used to move the water out of the pipes, while keeping gas pumping to customers by using other resources. The test is primarily to check for leaks.

August is also "call 811 month," according to PG&E, to alert anyone thinking of digging into the ground to call for inspections prior to doing so.

From the air, Wood checks for the proximity of agriculture and construction equipment as it relates to the pipelines. Each pipeline is at least three feet under the ground, and those lines could be in danger of exploding if anyone breaks ground intentionally or accidentally.

Similar to the natural gas explosion at a home in Carmel in March, PG&E recently told the City Council the gas had backed up in the pipes. The cause of the back up is still under investigation.

"If we see activities that we can't explain or that look like they pose risk, we will contact our ground patrol and have them respond," Wood added.