Know What’s Below: Understanding the Universal Colour Code for Buried Utilities

Before you start any digging project—whether it’s planting a tree, building a deck, or installing a fence—it’s crucial to know what lies beneath the surface. Across North America, a standardized colour code system is used to mark underground utility lines. These coloured flags or paint markings indicate what type of infrastructure is buried below, helping prevent dangerous and costly accidents.

Here’s a quick breakdown of the Universal Colour Code:

• Red – Electric power lines, cables, conduit, and lighting cables
• Orange – Communication, alarm or signal lines, cables, or conduit (including internet and telephone)
• Yellow – Natural gas, oil, steam, petroleum, or other flammable material
• Green – Sewer and drain lines
• Blue – Potable (drinking) water
• Purple – Reclaimed water, irrigation, and slurry lines
• White – Proposed excavation (used to outline the area you plan to dig)
• Pink – Temporary survey markings

Understanding this colour code is more than just handy—it’s a vital part of staying safe. Striking a gas or electric line can lead to serious injuries, service disruptions, and expensive repairs. That’s why it’s so important to ClickBeforeYouDig.

In Alberta, submitting a locate request through Utility Safety Partners is free and easy. Within a few days, utility companies will mark the locations of underground lines using the colour-coded system. These markings help ensure your project proceeds safely for you, your family and your community.

Take the time to recognize these colours and respect the markings. A few minutes of planning could prevent a major incident.

Know what’s below. ClickBeforeYouDig. And always dig with care.

Mike Sullivan, President – Utility Safety Partners