Passive EM Sweep Locating in Duncan, BC

EM line tracing is largely soil-independent — it follows the signal on the conductor regardless of what's around it — but GPR, the half that finds non-conductive plastic and clay lines, is very soil-sensitive. Duncan sits on predominantly Cowichan Valley alluvium — sands and silts with seasonal saturation. Summer scans reach well into the alluvium; winter saturation shortens range. Farm and First Nations lands carry generations of undocumented lines. So in Duncan we lean on EM for the metal and tracer-wired lines and set realistic GPR expectations for the plastic — which is exactly why running both methods matters here.

The local mix follows the building stock: Compact heritage downtown, surrounding farm parcels, and valley acreages with legacy water systems. Underneath that, the everyday Duncan locate is private water and irrigation services, power to outbuildings and gates, gas to outdoor features, and the plastic mains that need GPR or sonde tracing — the private-side utilities no public locate covers.

Yes. BC One Call marks member utilities' public lines to the property line across Duncan and all of BC — it does not locate the private services beyond it, which is where most strikes happen. The EM + GPR clearance survey covers those private lines. Use both: BC One Call for the public locates, a private dual-method locate for everything on your side.

Province-wide pricing — no regional premium for Duncan or anywhere in the Vancouver Island. A focused clearance (a dig area, a fence line) starts in the low-to-mid hundreds; full-site mapping and SUE-grade work are quoted by scope. The free phone consult (604-239-9934) gives a firm number in about five minutes. Mon–Sat, 8am–6pm PT.

Because its job is safety-first discovery, not identification. The power-mode sweep flags energised cables — the highest-consequence strike risk — before anyone applies a signal or breaks ground, and the radio sweep catches conductive lines you didn't know were there. It's the fast opening pass that tells the active-locating and GPR work where to concentrate.

No — passive detection needs the line to carry or re-radiate a signal, and bare plastic carries nothing. Plastic water mains, PVC/clay sewer, and similar non-conductive utilities are invisible to every EM mode; they're found by GPR imaging or by tracing a tracer wire or sonde. A passive 'all clear' is never a real all-clear on its own, which is exactly why we never stop there.