EM vs GPR locating. It's not either/or — here's why.

Because GPR shows you an object, not an identity. On a radar image, a metal water line and a metal gas line look alike — and in a congested corridor, GPR alone can't tell you which reflection is which, or trace one specific line to its source. EM puts a signal on the one line you care about and follows only that line, with identity and precision GPR can't match on conductors. They're complementary: EM for identity and conductive precision, GPR for everything non-conductive and the unknowns.

Because EM is completely blind to anything that doesn't conduct — and the lines crews most often strike are exactly those: plastic water services, PVC and clay sewers, concrete ducts. None carry an EM signal, so an EM-only locate simply never sees them. GPR images them. Skipping GPR to save time is how a locate misses the plastic main and the dig finds it instead.

Different kinds of accuracy. On a clean trace of an isolated conductive line, EM gives excellent route and identity precision. GPR's accuracy depends heavily on soil — superb in dry sand, limited in wet clay — and excels at imaging and finding the unexpected rather than tracing a known line. Asking which is 'more accurate' is like asking whether a tape measure or a camera is more accurate; they measure different things. Used together, they verify each other, which is the real accuracy gain.

It limits it, sometimes severely. GPR relies on radar penetrating the ground, and conductive wet clays and silts absorb that energy fast, shrinking useful depth; dry sands and gravels let it reach much deeper. That's why a responsible locator states GPR expectations per site rather than promising a fixed depth — and why pairing with EM matters: EM tracing is largely soil-independent, so it carries the conductive lines even where GPR struggles.

Usually yes, because even a backyard has both kinds of line: the metal gas line EM traces and the plastic irrigation or water service only GPR or a sonde will find. The cost difference between EM-only and dual-method on a small job is minor; the cost of striking the plastic line the EM-only locate couldn't see is not. For anything you'll dig, both methods are the honest small-job answer.

Dual-method IS our standard locate, not an upsell — the clearance survey runs EM and GPR together because a conductive-only locate isn't a complete one. Pricing is by scope (area, complexity, deliverable), province-wide with no regional premium, and the free phone consult gives you a firm number in five minutes. You're paying for a complete picture, which is the only kind worth digging on.