How buried lines are found
Utility Locating Methods
Nothing underground answers to one instrument. Radar images plastic pipe and voids, electromagnetic tracing follows metal and tracer wire, acoustics finds pressurized leaks, and a vacuum-excavated test hole is what turns any of it into a measured depth. Each method below covers what it does, where it fails, and which utilities it finds.
Pick the method that is closest to your work, or leave it blank and describe the site. The locating company confirms what the ground actually calls for.
Locating methods
8 ways to find what is buried
Not sure which one your job needs? Leave the method blank on the request, or pick whichever is closest and the locating company confirms what the site actually calls for.
Private Utility Locating
Everything past the meter, found and marked.
Private utility locating finds and marks the buried lines on your side of the meter, the ones a one-call ticket does not cover. Locators combine electromagnetic tracing with ground penetrating radar to sweep a site before anyone breaks ground.
Get quotesGround Penetrating Radar
Radar imaging that finds plastic pipe and voids.
Cart-mounted radar that images the shallow subsurface by reading reflected pulses. It finds non-conductive targets such as PVC, clay tile, concrete, and tanks that electromagnetic locating cannot trace.
Get quotesUtility Mapping
Turn a locate into a permanent CAD and GIS record.
Survey-grade capture of located underground lines, delivered as georeferenced CAD, GIS, and PDF records. Paint washes away in weeks; the map stays with the site.
Get quotesLine Marking
APWA color-coded paint and flags on the ground.
The field output of a locate: traced utility routes transferred to the surface as paint, flags, and stakes in the APWA Uniform Color Code, with identity, size, and estimated depth written alongside.
Get quotesSubsurface Utility Engineering
ASCE 38 quality levels, sealed and survey-grade.
Subsurface Utility Engineering investigates and depicts existing utilities to ASCE 38-22, classifying every segment by quality level from records research (QL-D) up to physically verified position at a test hole (QL-A). The deliverable is a sealed, surveyed drawing used for design, not marks on the ground.
Get quotesLeak Detection
Pinpoint the leak, dig one hole instead of the run.
Acoustic correlation, ground microphones, tracer gas, and pressure testing used to pinpoint where a pressurized water or gas line is losing product. The output is a marked point small enough to excavate, not a trench down the length of the line.
Get quotesConcrete Scanning
Scan the slab before you core, cut, or drill.
High-frequency ground penetrating radar run across a structure rather than the ground, mapping rebar, post-tension tendons, conduit, and voids inside the concrete. It is done immediately before a penetration so the crew knows where it is safe to cut.
Get quotesVacuum Potholing
The test hole that turns an estimate into a measurement.
A small hydro or air vacuum excavation that exposes a buried line so its depth, material, and size can be measured instead of estimated. No bucket, auger, or blade reaches the pipe, which is why it is the standard way to dig inside the tolerance zone, though pressure and standoff limits still have to be observed around cable and coated steel.
Get quotesBefore any of it
Call one-call first. Private locating covers the rest.
Every dig starts with a locate request to your state or provincial one-call center. The ticket is free, it is required by law before excavation in most jurisdictions, and it puts the member utilities on notice to come out and mark the public lines they own, which generally ends at the meter, the pedestal, or the right-of-way.
None of the methods on this page replace that ticket. What they cover is the other half of the site: the service run past the meter, yard and parking lot lighting, irrigation mains and valve wire, septic tanks and laterals, private fire loops, and whatever a previous owner buried without telling anyone. Nobody is coming to mark those, because nobody else owns them.
One-call programs differ by jurisdiction, and each of our state and province pages names the program and number that applies there.
The other way in
Or start from what you need found
Most people do not shop for an instrument. If you know the line but not the technique, start here and the method follows from the target.
- Water Line LocatingFind the water line before the excavator does.
- Gas Line LocatingThe highest-stakes line on the property.
- Electrical Line LocatingLive power is easy to find. Dark conduit is not.
- Sewer & Septic LocatingLaterals, tanks, and drain fields with no map.
- Fiber & Telecom LocatingGlass carries no signal. Locate before you bore.
- Irrigation Line LocatingPlastic pipe, no map, and a wire worth following.
Not sure which method you need?
Describe the site and what has to be found. We send your request to locating companies that cover your area, and they send you their own quotes. Free to submit, no obligation to hire.