Underground Utility Line Color Codes And What They Represent

If you’ve noticed different colored paint marks or flags on your job site…they’re utility marking paint and utility marking flags used for underground utility line identification. As part of JULIE’s safety protocols, they serve as a guide of where it may—or may not—be safe to dig.

According to Illinois law, anyone who plans to put a shovel in the ground is required to contact JULIE to have underground utility lines marked for FREE before they start excavation. The excavator actually doing the digging must be the one to contact JULIE. That could be a contractor, a fence or pool installer, any professional hired for a job that requires excavation, a city or town, or a utility company.

After being notified by JULIE, utility companies that supply services like electricity, natural gas, water, phone, cable TV, Internet, fiber optics, and more send representatives out to mark the location of their underground utility lines following the APWA uniform utility line color code system. They use utility marking flags, stakes or utility marking paint to indicate approximately where underground utility lines are buried. These markings act as a guide for the excavator so they can avoid striking a critical service line. If a utility company marks an OK or NO, that means they have no underground utility lines in that area and it may be safe to dig.

Companies are responsible for underground utility line identification only for lines they own or maintain and JULIE personnel do not visit dig sites nor locate any underground utility lines. Private lines, which are underground lines installed after the operator or their contractor have installed the basic service, may also be on the job site. Click here to see examples of private lines and how to identify them.

The utility line color code system for utility line identification was created as an easy way for excavators to quickly distinguish what areas of their job site are safe for digging. To reduce the risk of causing an accident or damaging an underground utility line, always contact JULIE before you dig at least two business days before you’re scheduled to start your excavation project.

What does each color represent? Here is a summary.