Site size and number of utilities
The bigger the area and the more services running through it, the more time a thorough locate takes. A single line to a meter is quick; clearing a whole site with multiple crossing utilities, or surveying a campus, is a larger scope.
Congested corridors — where power, gas, water, telecom and private services share a trench — take more care to separate and trace accurately.
Metallic vs. non-metallic, and whether GPR is needed
EM locating handles metallic and tracer-wired lines efficiently. The moment non-metallic pipe is involved — plastic water mains, clay sewers, fibre ducts — GPR is added to find what EM can't, which expands the work. Sites with a mix of materials need both methods.
Concrete scanning before coring or cutting is its own scope: each penetration location is scanned for rebar, post-tension cables and conduit, so the number of cores or cuts drives the time.
Access, ground conditions and deliverables
Difficult access, traffic control, confined spaces and depth all add to the work. Ground conditions matter for GPR — clay and saturated soils attenuate the signal and slow interpretation, while granular ground reads more cleanly.
Finally, the deliverable scales the scope: marks on the ground are the baseline; an as-located map, depth estimates, a quality-level utility survey or GIS-ready data are progressively larger pieces of work.