Take these steps to prevent damaging underground lines

California law requires that you call 811 at least two business days before starting your excavation project. Whether you are planting a tree or a garden, digging holes for fence posts or driving stakes for concrete, call 811 at least two business days before you plan to start your project. For more information visit California 811.

Here are the steps you need to take:

Take these steps to prevent natural gas leaks

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Call 811

Whether you are planting a tree, digging holes for fence posts or driving stakes for concrete, call 811 at least two business days before you plan to start your project. Call 811 at least two business days before you dig – the service is free.

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Identify and mark your digging area

Identify and mark your digging area with a white substance such as chalk, spray paint, flour or marking whiskers, tags, stakes or any combination.

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Leave the marks in place

PG&E and other companies will use colored utility flags, stakes or paint to mark underground lines following the American Public Works Association Uniform Color Code (PNG, 130 KB). Please leave the marks in place until you are finished digging. The marks are valid for 28 days.

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Use handheld digging tools when digging within 24 inches of the outside edge

Only use hand digging tools, such as shovels, within the 24-inch zone.  After finishing your project, carefully backfill and compact the soil.

Natural gas transmission pipeline markers

You can spot PG&E's larger transmission pipelines by looking for pipeline markers. They specify the approximate or offset location; however, not all pipelines follow a straight path between markers. These markers also indicate the need for extra care when digging in the area.

map of transmission pipelines

See if there are transmission pipelines nearby

Use our interactive online map to find out if there are natural gas transmission pipelines in your area.

View map

image of ground marker

Take extra care when a marker is present

Our bright yellow markers indicate a natural gas transmission pipeline is nearby, and display our 24-hour emergency gas hotline number.

Gold Shovel Standard Safety Program

Gold Shovel Standard safety program

We created this first-of-its-kind excavation safety program to reduce accidents and protect underground gas and electric systems.

Free 811 Safety Posters

Free 811 safety posters

Post these informative posters in the workplace and on the jobsite to remind workers that it's necessary to call 811 before digging.

Download English posters

Contractor gas safety poster (PDF, 3.1 MB)
Markings brochure (PDF, 1.3 MB)

Download Spanish posters

Folleto sobre seguridad para contratistas (PDF, 357 KB)
Folleto sobre marcaciones (PDF, 1.3 MB)
Common Ground Alliance

Common Ground Alliance

Common Ground Alliance is a member-driven association committed to saving lives and preventing damage to underground infrastructure by promoting effective damage prevention practices.

Recognize signs of a natural gas leak

Please report any signs of a gas leak immediately.


We add a distinctive, sulfur-like, rotten egg odor so you can detect even small amounts of natural gas. However, DO NOT rely only on your sense of smell to detect the presence of natural gas.

Some people may not be able to smell the odor due to a diminished sense of smell, olfactory fatigue (normal, temporary inability to distinguish an odor after prolonged exposure), or because it is masked or hidden by other odors that are present. Also, certain conditions in the pipe and soil can cause odor fade—the loss of odorant so that it is not detectable by smell.


Pay attention to hissing, whistling or roaring sounds coming from underground or from a gas appliance.


Be aware of dirt spraying into the air; continual bubbling in a pond, creek, puddle or other source of standing water; as well as dead or dying vegetation in an otherwise moist area.

What to do if you suspect a gas leak or damaged gas leak or damaged pipeline

  • If you suspect a leak, or you accidentally dent, scrape or damage a gas pipeline in any way, alert others in the area and leave immediately.
  • Until you are a safe distance upwind, do not light a match, use a cell phone or flashlight, operate a vehicle or use any electronic device near the leak.
  • Call 911 for emergency assistance and then call PG&E at 1-800-743-5000.