Utility Mark

Utility marks are the visible result of the utility locate process. Locators use spray paint, flags, stakes, and sometimes whiskers (short wire markers) to indicate where each utility runs underground. The marks are placed directly above the estimated centerline of the utility and extend along its path through the excavation area.

The marks include the APWA color code identifying the utility type, the utility owner's name or abbreviation, and sometimes additional information such as the size of the pipe or the voltage of the cable. The marks are temporary and will fade or be destroyed over time, which is why most locate tickets have an expiration date, typically 10 to 30 days depending on the state.

It is critical to understand that utility marks indicate approximate position only. The actual utility may be offset from the mark by up to the tolerance zone width (typically 18 to 24 inches on each side). This is why non-destructive excavation methods like hydrovac must be used within the tolerance zone. Treating utility marks as exact positions and digging mechanically near them is a leading cause of utility strikes.