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How to Interpret Utility Marking Colors

utility marking colors
June 29, 2023

If you are familiar with utility locator marks you know that it can be difficult to correctly interpret them. Utility locator marks and symbols are part of a national uniform marking system used by utility locating organizations throughout the US, such as American Public Works.

The purpose of the marking system and APWA uniform color codes is to help utility-related personnel to quickly and safely identify, locate, and protect buried utility lines. This helps engineers and project managers plan for proposed excavation of constructions. By understanding the meaning behind the various utility locator marks and symbols you can more effectively interpret what’s below the surface.

The Basics of Utility Marking Colors and Symbols

Utility locator marks are painted markings used for marking underground utilities, including electric, gas, water, phone, sewer, cable and fiber. These symbols are also created using flags, stakes and/or other markers. Underground utility color codes are used to indicate different utilities, including gas (red), electric power lines/cables (orange), water (blue), telecom (yellow), wastewater (purple), and green is sewer lines.

Decoding Markings and Colors for Underground Utilities

To understand what these symbols and marks mean, a specialized reference guide is needed. Each mark will include information about the type of utility, the size of the line, and other details. Typically, the guide will have a unique identifier for each symbol, as well as the colors that are associated with it.

When looking for these symbols, it is important to pay close attention to the size and shape of the symbol, the number of colors being used, and the presence of letters and numbers. These are all clues as to what kind of utility is located in the marked area.

Sometimes, these locator symbols are accompanied by flags or stakes that are used to create a “centerline” of a utility. This centerline is created using the “common point” of the two symbols. The distance between the symbols is used to measure the approximate distance of the line. Also, note that this centerline is located somewhere in the middle of the two symbols—not where the symbols are placed directly on top of one another. All utility locator symbols should be read from left to right and in a clockwise fashion.

If the flags around the symbol are red, blue, yellow, or other colors, they may be indicating types of other features (like a private well or a manhole). Alternatively, they may be warning flags that indicate buried utilities that have not been marked with symbols.

It is important to remember that these types of symbols should only be interpreted by experienced professionals. A professional is the only one who can make sure the markings are found and interpreted correctly.

UtiliSource: Utility Locator Services

Take the guesswork out of your project planning and save time and money with UtiliSource’s professional utility locating services. Contact us today to request a quote and get the peace of mind that comes with knowing exactly where essential utilities are located on your property.

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