What Is Locating and Marking? Utility Locates Explained

Under almost every street, yard and job site there is a web of buried lines: natural gas, electrical cables, water and sewer pipes, telephone and fibre lines, and sometimes pipelines. You cannot see them, and old drawings are not always right. Striking one can cause serious injuries or deaths, fires and explosions, power and internet outages, and costly damage.

Locating means finding where those lines are, using utility records and locating equipment. Marking means showing their position on the surface with paint, flags or stakes in a standard colour, so the crew can see exactly where not to dig with power equipment.

Any work that breaks the ground is called ground disturbance. That includes excavating, trenching, drilling, boring, augering fence post holes, driving stakes and even deep landscaping. All of it should start with a locate.

A one-call service is a single point of contact that passes your request on to the utility owners in the area. Each owner then locates and marks its own lines, or tells you it has none there. Private lines, such as a line from a house to a garage, may not be covered, so you may need a private locator as well.

Plan ahead. Locates take time, and each service sets its own notice period and rules. Do not start digging until every owner has responded and you have the locate information on site.

How locators find lines. Most locates use an electronic locator. A transmitter puts a signal onto a metal pipe or cable, either by connecting to it directly or by sending the signal through the ground, and a receiver traces that signal along the surface. Locators also use utility records and maps, and sometimes ground-penetrating radar. Each method has limits. Plastic pipes without a tracer wire, lines close together, deep lines and poor records can all make a locate less accurate. That is why marks show an approximate position and why careful digging near them still matters.

Locate marks use a common colour code so anyone on site can tell what kind of line is below. The colours most often used in Canada are:

• Red: electric power lines and cables.
• Yellow: gas, oil, steam and petroleum lines.
• Orange: communication lines, such as telephone, cable TV and fibre.
• Blue: drinking (potable) water.
• Green: sewer and drain lines.
• Purple: reclaimed water and irrigation.
• White: the proposed dig area, marked by the excavator.
• Pink: temporary survey marks.

Colours and symbols can vary by province and by utility owner, so always read the locate sheet that comes with the marks. A mark shows the approximate position of a line, not its exact depth or width.

Marks are where safe digging starts, not where it ends. Locating equipment has limits, and lines can be deeper, shallower or wider than the marks show. Good practice includes:

• Keep locate paperwork on site and check that the marks match the work area.
• Protect the marks. If they fade or get damaged, request a new locate.
• Near marked lines, expose them with hand digging or hydrovac (vacuum excavation) before using power equipment.
• Follow the safe distances in your provincial ground disturbance rules and the utility owner’s instructions.
• If you hit or damage a line, stop work, move people away, and call the utility owner and emergency services if there is any danger, such as leaking gas.

Anyone who plans, supervises or does ground disturbance work. Common jobs include:

Supervisors and planners benefit as much as crews. Most line strikes are prevented in the planning stage, by requesting locates early and getting the right permits.

The Gama Safety Locating and Marking course takes about 45 minutes and has five modules:

1. Introduction to Locating and Marking: why utilities must be located before digging and the risks of a strike.
2. Pre-Work Planning and Permits: planning ground disturbance work, requesting locates through a one-call service and getting the right permits.
3. Locating Equipment and Technology: the tools used to find buried utilities and their limits.
4. Marking Procedures and Best Practices: paint, flags and stakes, and reading the colour code correctly.
5. Site Hazards and Safety Precautions: managing site hazards and digging safely with hand digging or hydrovac.

The course gives you the knowledge. Always follow your provincial ground disturbance rules, the utility owner’s instructions and your employer’s procedures on site.

1. Enrol in the online Locating and Marking course and start right away on any device.
2. Learn at your own pace. It takes about 45 minutes, and your progress saves automatically.
3. Pass the final exam with 80% or better. Retakes are unlimited and free.
4. Download your certificate right away. A physical wallet card is mailed to you free.

There is no single national expiry date for this training. Many employers ask for a refresher every 1 to 3 years. The course is recognized by employers across Canada and available in English, French, Spanish, Punjabi, Hindi, Mandarin and more. Team pricing starts at 2 seats. Call 1-866-661-9803 or email info@gamasafety.ca.