In British Columbia, 'Call Before You Dig' — BC One Call — is the mandatory first step before any excavation. But BC One Call covers only public utilities to the property line. On private property, in multi-tenant developments, and on sites with legacy installations and as-built drawings that don't match reality, calling before you dig is necessary but not sufficient. Ground-Penetrating Radar is what fills the gap.
What BC One Call Does and Doesn't Cover
When you submit a locate request through BC One Call, the participating utilities — BC Hydro, FortisBC, local telecoms, and municipal water and sewer in most areas — send technicians to mark their infrastructure on your site. This is reliable for main-line public utilities.
It does not cover:
- Private service laterals within the property boundary (gas branch from metre, electrical from panel, water from metre pit to building)
- Owner-installed irrigation mains and laterals
- Private drainage and grease trap piping
- Fibre and copper communications on private property
- Legacy buried services no longer in active use but still carrying product
- Services installed before reliable as-built records existed
These uncovered services are exactly where utility strikes happen on private property.
What a GPR Pre-Excavation Survey Finds
Ground-Penetrating Radar transmits radio pulses into the ground and reads the reflections, producing a continuous cross-section of the subsurface. It detects:
- Non-metallic pipes (PVC, HDPE, clay, concrete) that electromagnetic methods cannot find
- Metallic pipes in locations not covered by BC One Call
- Electrical conduit and duct banks
- Communications cable bundles
- Voids and loose fill that could be unstable during excavation
Combined with electromagnetic locating (for conductive lines), GPR provides the most complete subsurface picture available before breaking ground.
Typical Situations Where GPR Pre-Excavation Scanning Is Needed
- Landscaping projects involving trenching on private property
- Slab-leak repair requiring saw-cutting or jack-hammering
- Addition and renovation foundations
- Underground parking structure work
- Commercial sites where legacy services may exist
- Any work within 1 metre of a post-tension cable zone in concrete
- Heritage or industrial sites where no reliable as-built drawings exist
What the GPR Scan Process Looks Like
- We review available as-built drawings and note known utilities and their entry points
- We perform EM locating on all conductive lines accessible from a known connection
- GPR sweeps the excavation zone in a grid, both along and across the likely service directions
- We mark identified utilities on the surface using BC One Call colour codes and note estimated depths
- We flag zones of uncertainty — areas where signal interpretation is less confident — to guide conservative excavation
- A scan report with a surface sketch or digital plan is produced for the excavation crew
The Real Cost of Not Scanning
Utility strikes carry direct costs (repair of the struck line, service restoration, emergency excavation) and indirect costs (project delays, contract disputes, regulatory fines under the BC Safety Standards Act, and property damage from struck gas or electrical lines). Most utility strikes on private property involve services not covered by BC One Call — exactly what GPR finds.
The cost of a GPR pre-excavation survey is almost always a fraction of the cost of a single utility strike. Contact LeakInspections.ca at 604-239-9934 to schedule a pre-excavation survey for your BC project.