Knowing the color codes for marking underground utilities in North Carolina is essential for anyone involved in excavation work. Properly marking utilities before digging helps prevent damage to vital infrastructure like gas lines, water mains, and telecommunications cables. This article will provide a comprehensive overview of the standardized color codes used for marking underground utilities in NC.
North Carolina has adopted the American Public Works Association’s Uniform Color Codes for marking underground utility lines. This standardized system is used across the United States to promote safety and prevent costly damages. The uniform color codes are as follows:
| Color | Utility Service |
| Red | Electric power lines, cables, conduit, and lighting cables |
| Orange | Telephone, alarm or signal lines, cables, or conduit |
| Blue | Potable water lines |
| Green | Sewers and drain lines |
| Yellow | Gas, oil, steam, petroleum, or other hazardous liquid or gaseous materials |
| Purple | Reclaimed water, irrigation, and slurry lines |
| White | Proposed excavation limits or route |
These color codes must be used by utility companies when marking their underground lines, and excavators must be familiar with them when digging around buried utilities. Proper marking is required by law in North Carolina through the state’s “Call Before You Dig” program.
The Importance of Proper Utility Line Marking
Marking underground utilities with the correct colors is extremely important for safety. Striking a utility line during excavation work can injure workers, disrupt service to entire neighborhoods, and cause expensive repairs. For example, a damaged gas line may lead to an explosion or leak. A cut water main can flood an area and leave residents without water. And a severed fiber optic cable can knock out internet, telephone and TV service.
In addition to protecting safety and services, proper utility line marking also prevents costly penalties. North Carolina’s “Call Before You Dig” law requires excavators to notify utility companies of planned digs at least three business days in advance. If underground utilities are then struck, the excavator can be held liable for repairs. However, if the utilities were not properly marked, then the utility company may be fined up to $5,000 by the state.
How Utility Lines are Marked in North Carolina
Marking underground utility lines in NC involves three main steps:
- The excavator calls 811 at least 3 business days before digging.
- Local utilities send locators to mark lines at the dig site.
- The locators use the standard color codes to mark utility locations.
Locators may spray paint colored lines on streets and sidewalks showing utility routes. Or they may place colored flags or stakes in the ground above buried lines. Temporary marking paint is the most common method. The American Public Works Association recommends minimum line widths of 1 inch for temporary markings and 3 inches for permanent markings.
In addition to color, locators may indicate the specific type of utility with letter codes:
| Letter | Utility Meaning |
| E | Electric |
| G | Gas |
| P | Petroleum |
| T | Telecommunications |
| W | Water |
| S | Sewer |
Lines may also be marked with additional symbols to show the number of cables, width, or other details about the utility. Excavators should look for and understand these symbols when digging.
Who Marks Utility Lines in North Carolina
The following are the main utility companies responsible for marking their underground infrastructure in NC:
- Duke Energy – Electric lines
- PSNC Energy – Natural gas lines
- CenturyLink – Telephone and fiber optic lines
- State/local municipalities – Water, sewer and reclaimed water lines
- AT&T, Spectrum, etc. – Telecommunications lines
These companies and agencies have dedicated teams of locators who will visit dig sites after 811 calls and mark lines as required. Excavators should also contact utilities directly if lines appear to be missing or markings become obscured.
How Long Do Utility Markings Last
The markings made by locators are considered temporary and valid for a limited period. In North Carolina, the state’s Call Before You Dig law considers utility markings valid for 15 working days from when lines were marked. After 15 days, excavators must call 811 again before digging to have lines re-marked if work is still ongoing.
Markings may deteriorate or lose visibility in less than 15 days due to factors like weather and traffic. If markings are no longer visible, excavators should halt digging and call 811 for re-marking. Work should not resume until utilities are re-located and color-coded.
Exceptions to the Utility Color Codes
While the APWA color codes are standardized across the US, there are some exceptions in certain locations. In North Carolina, the following differences apply in some jurisdictions:
- City of Raleigh – Uses pink instead of red for electric lines
- City of Concord – Uses pink instead of red for electric lines
- City of Rocky Mount – Uses gray instead of orange for telecom lines
- City of High Point – Uses pink for unknown/unidentified lines
Excavators should be aware of these variations within city utility systems. Checking with local providers for any unique marking codes is a good practice.
Special Marking Scenarios
Certain types of dig sites and projects require additional care with utility line markings:
- Large sites – Marking may be done in segments as work progresses across a large site.
- Long, linear projects – Such as new cable or pipeline runs. Marking may occur over many miles.
- Rural areas – Private lines like farm drainage pipes may not always be located.
- Emergency digs – Utilities must respond quickly when possible.
Excavators should communicate with locators in such cases to ensure adequate and timely marking. Critical infrastructure or high-priority lines may also be marked with additional indications like flags or stakes.
Locating Underground Utilities Without Color Markings
In some cases, underground utilities may not be marked with colored paint or flags before digging. This includes:
- Emergency excavations needed before locators can respond
- Rural areas with private lines unknown to utilities
- Old abandoned lines from past development
In these situations, excavators have additional tools at their disposal:
- Utility maps – Show general utility zones but not exact locations
- Pipe locators – Electronic devices can detect buried metal and plastic
- Ground-penetrating radar – Provides images of what’s underground
- Hand digging – Carefully uncover utilities by digging with shovels
However, the best practice is to have utilities marked in advance and avoid undetected dig-ins. When in doubt, excavators should call 811 again and confirm all lines are properly marked per the color code standard.
Conclusion
Adhering to the American Public Works Association’s utility color codes is crucial for safe digging practices in North Carolina. All excavators must recognize the meanings of each colored marking. While minor regional variations exist, red, orange, blue, green and yellow provide universal utility line identification across the state. By calling 811 before projects and using caution around color-coded lines, contractors and homeowners can protect vital infrastructure and avoid injuries, service interruptions, and legal penalties. Following the standardized color codes supports efficient project completion and is essential for preventing damages.