Overview
Ground disturbance work carries serious risk when buried utilities, unstable soil, or unmarked hazards aren't identified before the first cut. A single strike on a gas or electrical line can injure workers, interrupt service to an entire neighbourhood, and expose the contractor to significant liability. This guide walks through the planning and execution steps every crew should follow, from locate requests through backfill and close-out.
It applies to any work that penetrates the ground surface — excavation, trenching, augering, driving posts or anchors, and even landscaping work deeper than a shovel blade. If soil is being displaced, this process applies.
Planning & locates
Before any ground is broken, a locate request must be submitted through Alberta One-Call, and results should be documented and shared with every worker on site. Locates are only valid for a limited window, so timing your dig to the confirmed window matters as much as requesting it in the first place.
Locates are the floor, not the ceiling. Private lines — site services, irrigation, security wiring, and abandoned infrastructure — are often not registered with One-Call and require a private locate service or historical site drawings to identify.
- Submit the One-Call locate request at least the required number of business days before the dig.
- Confirm the locate window and schedule work within it — request a re-locate if the dig slips.
- Arrange private locates for unregistered services (site power, irrigation, comms).
- Walk the dig area with the crew and review markings before equipment arrives.
- Photograph all locate markings — flags fade and paint washes away.
Safe excavation practices
Hand-digging or hydrovac excavation should be used within the tolerance zone around any marked utility, and a spotter should remain present whenever mechanical equipment is operating nearby. Once a utility is exposed, it must be supported and protected — never left hanging unsupported across an open trench.
Trenches deeper than regulated thresholds require sloping, benching, or a protective shoring system, and a competent person must inspect the excavation at the start of each shift and after any event that could affect stability — rain, freeze-thaw, or nearby vibration.
If you contact a buried utility
Stop work immediately and keep everyone away from the contact point. Do not attempt to repair, move, or backfill over the line.
If a gas line is struck: shut down equipment if safe to do so, evacuate upwind, eliminate ignition sources, and call the utility owner’s emergency line and 911. Report every strike — including near-misses and minor nicks to coatings — to the utility owner and document it in your incident reporting system.
Closing out the work
Once work is complete, backfill and compaction should be inspected and signed off before the site is closed out. Bedding material around exposed utilities must meet the utility owner’s specification, and warning tape should be reinstated at the correct depth.
Keep the locate ticket, dated photos of exposed utilities, and the signed backfill inspection together in the project file — sites operating under a COR or SECOR program should retain these records as part of their audit documentation.
Frequently asked questions
How long is a locate request valid for?
Locate requests through Alberta One-Call are typically valid for a limited window from the confirmed clearance date. Check your locate ticket for the exact expiry — if your dig is delayed past that window, you’ll need to request a re-locate before breaking ground.
What counts as a "tolerance zone"?
The tolerance zone is the buffer distance on either side of a marked utility line where hand-digging or hydrovac methods are required instead of mechanical excavation. Exact distances vary by utility owner, so confirm the specified tolerance on your locate documentation.
Do I need a spotter for hydrovac work?
Yes. A spotter should be present any time excavation equipment is operating near a marked utility, watching for signs of the line and communicating directly with the operator.
Are private lines covered by Alberta One-Call?
No. One-Call covers registered utility owners only. Private services — site power between buildings, irrigation, security and communication wiring — need a private locate contractor or verified as-built drawings.
What documentation should I keep after the job is done?
Keep the original locate ticket, dated photos of the excavation and utility exposure, and a signed backfill/compaction inspection record. Sites under a COR or SECOR program should retain these for a minimum of two years.
Forms & Downloads
Locate Request Log
Archived Versions
Version 2 - September 2023
Version 1 - March 2021