Equipment Used for Underground Utility Locates
At Know Before You Dig Locates, we use a combination of industry-proven technologies to trace, verify, and interpret buried facilities. No single tool is effective in all conditions and our technicians are trained to apply the right method based on facility type, soil condition, location, and known site risks.
EM Locate Equipment
EM locating is the most widely used method for tracing conductive utilities. It detects the signal, not the cable or pipe itself — which means training and interpretation are key. Our technicians use both active and passive EM locating to identify underground utilities in public and private spaces.
EM Locate equipment have the following key points:
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Track electromagnetic signals applied to a buried utility line or emitted naturally
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Ideal for conductive power, gas, telecom, water, and tracer wire-equipped infrastructure
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Risks include signal distortion, improper grounding, and misinterpretation of locate results
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Tolerance distances are assigned to compensate for inherent uncertainty
Sewer Locating Tools: Sondes, Push Cameras & Robots
Sondes:
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Signal-emitting probe for non-conductive sewer lines
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Works well in clay, plastic, concrete
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Limitations: stops at cast iron, weak signal if deep
Push Cameras with Integrated Sondes:
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Combines video and signal locating
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Essential for identifying blind T connections and verifying sewer line condition
Sewer Robots:
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Deep/large pipe access
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Lateral launch capabilities
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May require flusher trucks and CSE compliance
Duct Rodders
Flexible fiberglass rods with traceable wire for non-conductive conduit. Can attach sondes to the end of the rodder if necessary.
Ideal for:
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Empty PVC conduits
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Telecom and irrigation installs
Limitations: No visual confirmation and refusal cannot be interpreted.
Acoustic Pipe Locators
Designed for plastic water lines with no tracer wire. Sends pulsed vibration through the pipe; technicians trace the sound using a sensor and head phones.
Ideal for:
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Water services
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Fire mains
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Irrigation pipes
Limitations: high ambient noise, must isolate internal plumbing.
Ground Penetrating Radar
Ground Penetrating Radar sends high frequency radar pulses into the ground or concrete and interprets reflected signals to identify subsurface anomalies. GPR can detect both metallic and non metallic features, but it does not identify what the object is without interpretation and supporting methods.
GPR is commonly used to locate:
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Buried utility infrastructure where facilities are non conductive or untraceable
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Rebar and reinforcing steel in concrete slabs
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Post tension cables and tendons
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Grade beams, thickened slabs, and foundation elements
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Voids, trenches, and changes in subsurface materials
Locate & Mark Method:
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Rapid scanning along a suspected path or area
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Technician interprets radar hyperbolas and signal responses to mark probable locations
Mapping Method:
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Gridded survey processed through specialized software
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Produces depth slices and 2D or 3D models
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Most accurate method but requires additional time and site access
Limitations:
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Performance is reduced in wet, clay rich, or rocky soils
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Cannot positively identify the type of object, only the presence of an anomaly
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Results are interpretation dependent and should be verified with complementary methods
Magnetometers
Magnetometers detect ferrous metal objects and are used to locate targets that do not emit or carry an electrical signal. They are effective for identifying buried metallic features where electromagnetic locating methods are not applicable.
Used to find:
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Iron valve boxes and valve lids
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Manhole covers buried under pavement, soil, or asphalt
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Survey pins, monuments, and steel markers
Magnetometers are not used for tracing pipes or cables and cannot determine direction, depth, or connectivity. They are best suited for asset recovery, surface feature identification, and confirmation of buried ferrous objects prior to further investigation or excavation.