Dig Safe part 3: respect the marks

This is the third post in our Dig Safe series, in which we’re explaining what you need to know about clicking or calling before you dig. This week we’re looking at what happens when you request a locate, and the underground utilities are marked for you  – specifically what the marks mean and why they matter. 

Every time you dig in your yard, there’s a chance you could be digging around underground lines or cables. Each of these structures brings vital services, such as natural gas, electricity or water to your neighbourhood, and each could be damaged by unauthorized digging.

That’s why it’s always so important to call or click before you dig. You might be surprised how your simple request for the services to be marked sets in motion a streamlined process involving several companies.

Shortly after the notification is received by the One Call Center, the owners of all services in your area are contacted, and each will determine whether the work you’re planning could come anywhere close to their underground pipelines, lines or cables. If there’s any chance that you could damage their infrastructure, they come out to temporarily mark the location. In cities, they will usually mark with paint, but on farms and acreages you’re more likely to see pin flags or wooden stakes, as they’re easier to find.

Your colour-coded yard

If, when they’re done placing the markings, your yard ends up looking like a child’s drawing, it’s with good reason. Different colours represent different types of infrastructure, making it simple to identify each one. For instance, yellow indicates the presence of oil, gas, petroleum or gaseous materials. The image below shows the colours for each different type:

click before you dig colour code markings


According to Brad Watson, damage prevention specialist, pipe engineering at TransCanada Pipeline, this colour code was developed by the American Public Works Association and is now used across North America.

How close to the marks can you dig?

Each of the locators will provide documentation to explain the significance of their marks and how you should work around them.

As a general rule of thumb, it’s best to stay at least five metres from lines and cables, particularly if you are using digging equipment. Any closer and you will probably be required to excavate carefully by hand, and the owner of the infrastructure may require that their representative is on site to oversee the work.

How long do the marks last?

The marks are usually valid for two weeks from the date the site is marked, which can sometimes be extended to 30 days at the discretion of both the infrastructure owner and the requestor, depending on a number of factors. Some jurisdictions and facility types even allow up to 60 days. But whatever timeframe you’re given on the locate notice, if you start a new project outside that, it’s your legal requirement to submit another application.

One final word from Brad:

Making a locate request costs you nothing; not making a locate request can cost you everything

Stay tuned for next week, when we’ll be reviewing some of the myths and facts about safe digging. In the meantime, check out previous posts in this series: ‘ 5 facts about safe digging across the Canada/US border’ and ‘Dig safe: know what kind of pipeline you’re working around’.


The Canadian Energy Pipeline Association represents Canada’s transmission pipeline companies who operate approximately 119,000 kilometres of pipelines in Canada. In 2015, these energy highways moved approximately 1.2 billion barrels of liquid petroleum products and 5.4 trillion cubic feet of natural gas. Our members transport 97 per cent of Canada’s daily natural gas and onshore crude oil from producing regions to markets throughout North America.