Dig safely and prevent utility dig-ins
Utility contacts can be costly—and deadly. Underground utility contacts cost utility owners and contractors millions of dollars in repair and service disruption costs every year. Not only that, workers who contact buried utilities put themselves and the public at risk of injury or death. It’s your responsibility to dig safely to protect yourself, your crew, and the public.
Call 811 or place an online request before you dig or move earth in any way—even for small jobs.
- Oregon online request system: or.itic.occinc.com
- Washington online request system: wa.itic.occinc.com
This free service will arrange to have underground utility lines marked so you can dig a safe distance away. Call before you dig, blast, bore, trench, drill, grade, or excavate in any way. Even small jobs require a call.
Before you notify, pre-mark your proposed dig area with white paint, flags, or stakes.
This helps locators more easily mark the affected utilities.
Wait the required time for lines to be marked so you can dig a safe distance away.
- In Oregon and Washington, wait at least two full business days before digging, not counting the date that you notify 811, weekends, and legal holidays.
Once utilities are marked, respect the marks, hand expose to verify location, and dig with care.
Always contact your state 811 center before digging and for the most current requirements.
Notify 811 well ahead of digging so underground utilities can be marked and you can work safely.
Shocking fact:
Not all utilities are members of 811. You are responsible for notifying non-member utilities. For a list of these utilities, check with 811 in the state where you will be digging.
Pipeline markers indicate the need for extra care around natural gas transmission pipelines and some distribution lines.
These markers are usually found at roadways, railroad crossings, and other points along the pipeline route. For security purposes, pipeline markers do not show the exact location, path, depth, or number of natural gas pipelines in the area. In addition, pipelines may not follow a straight path between markers.
The markers provide a toll-free number for reporting problems 24 hours a day, 7 days a week.
Call this number if you notice any unusual or suspicious activities nearby or if you see construction-related activity and no utility personnel are on-site.
Like pipeline markers, online maps indicate the approximate locations of major natural gas pipelines.
To view these maps, visit the National Pipeline Mapping System website.
Pipeline markers and maps indicate only the general location of pipelines. Never use them as a substitute for notifying 811 to have all utility lines in your dig area located and marked.
Shocking fact:
Most pipeline leaks are caused by accidental damage from excavation, construction, or farming activities.
Utility locator markings protect you.
Make sure you and your crew know how to read utility locator markings and know the American Public Works Association (APWA) uniform color codes for marking underground utilities. Color code charts are usually available from your local one-call utility locator service.
Locator flags are placed within paint marks.
If you find flags outside the borders of locator markings, someone may have tampered with them. Contact your local one-call utility locator service.
| APWA Color Code for Locator Marks | |
| Red | Electric power lines |
| Pink | Temporary survey markings |
| White | Proposed excavation |
| Yellow | Gas, oil, or steam |
| Blue | Potable water |
| Green | Sewers and drain lines |
| Orange | Communication lines, cables, or conduit |
| Purple | Reclaimed water, irrigation, and slurry lines |
Utility locator markings protect you from injury and prevent damage to underground utilities. Make sure you and your crew know how to read them.
Shocking fact:
You might arrive at a job site and find no markers, even AFTER utility locating has been completed. In this case, do not assume that the area is clear of utilities. Someone may have pulled up the flags or rubbed out the markings. Or the locator may have marked the wrong site. Check for indicators that buried utilities may be present, such as natural gas pipeline markers or utility meters. Contact the 811 service for assistance before starting work.
The tolerance zone protects buried utilities.
The tolerance zone provides a buffer zone to prevent damage to underground utilities that could result from nearby excavation. The tolerance zone is the width of a marked underground utility line plus a specified distance on both sides of that utility:
- In Oregon, this zone spans 24 inches surrounding the outside dimensions of all sides of an underground facility.
- In Washington, it spans 24 inches from the outside dimensions of both sides of an underground facility.
Hand dig prudently (or vacuum excavate) in the tolerance zone to determine the exact location and depth of marked utility lines.
The tolerance zone also protects you.
If you do not respect the tolerance zone, you risk contacting buried utilities. You also risk damaging them indirectly by removing supporting soil, which could cause the utility to bend or break. You could be injured or killed, and your company could be liable for any damages that occur.
To avoid utility damage, hand dig or use vacuum technology within the tolerance zone. Use a spotter to observe the excavation when heavy equipment is used near underground gas lines.
Shocking fact:
The width of the tolerance zone varies from state to state, and it is the digger’s responsibility to know what it is.
Check utility depth for yourself.
Before you can safely cross or work close to an underground utility, you must first verify its depth. Flags and locator marks tell you the direction the utility is running, but not how deeply it is buried. The only way to be sure of utility depth is to carefully expose it and see for yourself.
Proper hand-digging tools and techniques protect you and prevent utility line damage:
- Use a blunt-nosed shovel to loosen the soil, and a regular shovel to remove it. Do not use a pickax or any sharp or pointed digging tools. Do not stab at the soil or stomp on the shovel with both feet.
- Work with a gentle prying action and dig at an angle, so the shovel will slide along the surface of the wire, conduit, or pipe. Or, dig to the depth where you expect the utility line to be, but off to the side. Then use a prying motion to break away soil as you approach the utility laterally.
Use proper hand-digging tools and techniques to safely verify the depth of any buried utilities you must cross or work near.
Shocking fact:
Buried utilities are supposed to be installed at a specified depth. But in reality, utility depth is unpredictable. Improper installation, landscaping, regrading, repaving, erosion, and building development can all alter utility depth.
Vacuum equipment helps you verify utility depth.
Before you can safely cross or work close to an underground utility, you must first verify its depth. Flags and locator marks tell you the direction the utility is running, but not how deeply it is buried. The only way to be sure of utility depth is to carefully expose it yourself.
Vacuum equipment saves hand labor.
Vacuum technology can expose buried utilities without harming them. It uses suction and water pressure to remove soil down to the utility. Operate vacuum equipment only if you have been properly trained in its use.
If damage to a utility does occur, report it immediately.
Repairs can be made more easily while the utility is still exposed. Never try to fix a damaged utility yourself.
Be sure to wear proper personal protective equipment when using vacuum technology to verify utility depth.
Shocking fact:
Follow recommended practices for backfilling any utilities you uncover or expose with vacuum technology. Check with the local utility owner and municipality. Some facilities require a bed of sand, fine stone, or slurry.
Call 811 well in advance of directional drilling.
If you are planning to use directional drilling, call 811 well ahead of the job. Let them know about the equipment you will be using, and ask them to space locator marks closer together. This will help you see if the utility’s path shifts or turns suddenly.
Dig potholes so you can safely monitor the drill head.
A buried drill head makes it impossible to tell how close you really are to an existing utility. This makes it especially important to manually expose the line and watch as the drill string passes through. Keep a margin of safety by planning the bore to be a minimum distance of 36 inches from the utility. Watch the drill head cross during the initial bore and also during backreaming to ensure this minimum distance is maintained.
Calibrate the bore head and locating device at the start of each job.
Remember, the locating device can monitor the bore head on the initial pass, but may not be able to monitor the backream head.
Stay at least three feet away when boring parallel to buried utilities. Pothole utilities so you can monitor the bore head path and visually verify a safe distance.
Shocking fact:
Many drilling rigs have utility strike alarms that will alert you if you contact a buried power line. If this alarm sounds, assume you have hit a live power line and follow your company’s guidelines and the emergency procedures described on this website.
Report all gas pipeline contacts to NW Natural immediately. If gas is escaping, call 911. There’s no such thing as minor damage to a gas line. What looks like a small nick can result in a major fire and explosion hazard to the surrounding neighborhood. So if you or someone on your crew contacts a natural gas pipeline, take these steps:
- Warn others, leave the area immediately, and call NW Natural at 800-882-3377. If gas is escaping, call 911.
- Do not use matches or a lighter, start an engine, or operate any electrical device—even a phone. A spark could ignite the gas, causing a fire or explosion.
- Leave the excavation open, and do not attempt to stop the flow of gas or fix the pipeline.
- When you have reached a safe distance away, call NW Natural immediately at 800-882-3377.
- If gas is escaping, excavators are required by law to call 911.
- Call the utility even if there is no visible damage to the pipeline.
- Stay away from the area until safety officials say it is safe to return.
- Report the incident to your supervisor.
Never bury a damaged gas pipeline. Trying to cover up an accident can be dangerous and can lead to costly damages or criminal charges against you or your company.
Shocking fact:
An underground utility contact can happen even if you have dug in the area before or think you know the location of the lines. Landscaping, erosion, or other factors can change the location and depth of underground lines. Notify 811 to have all nearby underground utility lines marked before you begin the job.
Learn the warning signs of a gas leak.
NW Natural adds mercaptan, which has a highly recognizable sulfur-like odor, to natural gas to assist in leak detection. But don’t rely on your nose alone to detect a leak. Use your senses of sight and hearing, as well. Here are the signs:
- The distinctive odor of natural gas
- Dead or dying vegetation (in an otherwise moist area) over or near a pipeline
- Continuous bubbling in water
- A hissing, whistling, or roaring sound
- Dirt blowing into the air from a hole in the ground
- Exposed pipeline after an earthquake, fire, flood, or other disaster
- A damaged connection to a gas appliance
If you observe any of the above conditions, call 911 and then the NW Natural emergency phone number at 800-882-3377 from a safe location.
