Long-form guide · 12-minute read
Ground Penetrating Radar. See what's underground before you dig, drill, or cut.
GPR uses radar pulses to image subsurface features — buried pipes, voids, rebar, tanks, soil layers — without disturbing the surface. Multi-frequency antennas (200 MHz to 1.6 GHz) let us scan from 5 cm of rebar in concrete to 5+ metres below ground. Engineering-grade results with CAD-ready deliverables.
What is ground penetrating radar (gpr)?
Ground Penetrating Radar (GPR) is a non-invasive subsurface imaging technology that uses radar pulses to map what's beneath concrete, soil, asphalt, or pavement. The radar emits an electromagnetic pulse that reflects off subsurface objects with different material properties — pipes, voids, rebar, tanks — and the reflections are processed into a subsurface image.
GPR's defining feature is its multi-frequency capability. High-frequency antennas (1.6 GHz) produce extremely high-resolution images of the first 30–50 cm — perfect for rebar, post-tension cables, and embedded utilities in concrete. Mid-frequency (400 MHz) typically reaches 2–4 metres underground. Low-frequency (200 MHz) can reach 5+ metres in favourable soil — useful for deep utilities and buried tank surveys.
GPR is completely safe — it emits low-power radio-frequency energy, orders of magnitude weaker than a mobile phone or Wi-Fi router. No permits required. No surface damage. Cleared for use in occupied buildings and over live utilities. The technology has transformed leak detection, utility locating, concrete scanning, and buried-object detection across all 7 of our service verticals.
When you need ground penetrating radar (gpr)
If you're seeing any of these signs, professional detection is warranted:
- Planning to excavate, drill, or core through concrete or pavement
- Suspected buried oil tank (UST) at older BC property
- Slab leak suspected — need to map rebar and plumbing before repair
- Pre-coring scan required before drilling through a structural slab
- Need to locate buried utilities on private property (BC One Call doesn't cover)
- Void or sinkhole suspected beneath concrete (parkade, sidewalk, road)
- Lost or undocumented septic tank or buried infrastructure
- Engineering project requires subsurface as-built documentation
A $200 GPR scan averts a $50,000 utility hit
Hitting a buried utility during excavation is one of the most expensive mistakes in construction — direct repair costs, injury liability, project shutdown, and reputational damage commonly exceed $50,000. A pre-excavation GPR scan typically takes 1–2 hours and runs $400–$800. The math is overwhelming.
How we detect it
- 1
Project consultation
Phone consult to understand scope: pre-excavation locate, pre-coring scan, buried tank survey, void detection, etc. Determines which antenna frequency and survey method.
- 2
Site setup
On arrival, we mark the survey area, identify existing surface references, and select the appropriate antenna(s) — 1.6 GHz for concrete scans, 400 MHz for typical underground, 200 MHz for deep surveys.
- 3
Grid survey
Antenna is towed across the survey area in parallel transects, then perpendicular transects. The resulting 3D grid is processed into a subsurface map.
- 4
Real-time interpretation
GPR scans are interpreted in real-time on the cart-mounted display. Targets are flagged and marked at the surface immediately.
- 5
Surface marking
Located targets — pipes, voids, rebar, tanks — are marked at the surface in spray paint, flagging, or pin flags for your crew.
- 6
CAD deliverable
For engineering and as-built work, GPR data is exported to CAD (DWG/DXF) as a subsurface plan view. Combined with EM utility locator data for complete coverage.
Detection technologies we use
Multi-frequency GPR
1.6 GHz / 400 MHz / 200 MHz antennas selected per job. High frequency = high resolution shallow; low frequency = deeper penetration.
Learn moreElectromagnetic (EM) Locator
Complements GPR — finds energised metallic utilities (live cables) that GPR sees as 'just another object'. We run both on every utility-locate job.
Concrete Scanner (1.6 GHz)
Specialised handheld unit for pre-coring/drilling scans of slabs, walls, and beams. Maps rebar, post-tension cables, conduits.
Tracer Gas (for confirmation)
When GPR identifies a buried target that needs confirmation as a pipe with water flow, tracer gas confirms.
Learn moreCommon scenarios
Pre-excavation utility locate
General contractor about to trench across a commercial property for new fibre. GPR + EM survey found an undocumented 600V feeder 1.2 m off the planned trench line. One re-route saved $80K + injury risk + project shutdown.
Pre-coring concrete scan
Engineer needed three 100 mm cores through a post-tensioned slab. 1.6 GHz scan mapped all PT cables and rebar — cores were placed in clear zones. Zero structural compromise, zero rework.
Buried oil tank survey
Buyer's lawyer requested pre-closing oil tank scan on a 1958 home. GPR located a 1,000-litre buried oil tank in the side yard. Sale renegotiated with seller-funded removal.
Slab void detection
Building owner reported a 'soft' spot in a commercial parkade slab. GPR identified a 4 m × 2 m sub-slab void where compacted fill had washed out. Targeted concrete repair completed before any structural failure.
Typical pricing
Typical range. Final price quoted on the free phone consult.
- Small concrete pre-coring scan: $350–$500 per visit.
- Standard residential utility locate: $500–$900.
- Commercial / engineering surveys with CAD deliverable: $900–$1,500+.
- Large multi-acre surveys quoted by scope.
Frequently asked questions
How deep can GPR see?
Depth depends on antenna frequency and soil conductivity. 1.6 GHz: 30–50 cm with high resolution (perfect for concrete). 400 MHz: 2–4 m typical. 200 MHz: 5+ m in favourable soil. Wet clay and saline soils limit depth; dry sand and rock are excellent.
Can GPR detect plastic (PVC, PEX) pipes?
Yes — one of GPR's key advantages over EM locators. EM can't trace non-metallic pipes; GPR sees them based on density contrast with surrounding soil. We combine both technologies on every utility-locate job.
Is GPR safe?
Completely. Emits low-power radio-frequency energy — orders of magnitude weaker than a mobile phone or Wi-Fi router. No ionising radiation, no health risk, cleared for use in occupied buildings and over live utilities.
How accurate is GPR location?
Typically within 5–10 cm horizontal for shallow targets, 10–20 cm at depth. Depth estimates ±10% of target depth. Accuracy is a function of material conditions, antenna frequency, and operator skill.
Do I need a permit for a GPR survey?
No. GPR is non-invasive with no permit requirement. We can usually arrive, survey, and deliver findings within a single visit.
Does GPR work through concrete?
Yes — concrete is one of GPR's primary applications. 1.6 GHz antennas produce extremely high-resolution images of rebar, PT cables, conduits, and embedded utilities up to about 45 cm into a slab.
How much does a GPR survey cost?
Small concrete pre-coring scan: $350–$500. Standard residential utility locate: $500–$900. Commercial/engineering surveys with CAD deliverable: $900–$1,500+. Free phone consult gives a tight estimate in 5 minutes.
Can GPR find buried oil tanks?
Yes — buried oil tank (UST) detection is a major BC use case, especially for pre-purchase due diligence on homes built before 1960. GPR clearly images steel tanks and most fibreglass tanks at typical residential burial depths.
Will I get a report or just paint marks?
Both. Targets marked on the surface for your crew, plus a written report (PDF) with annotated images and plan-view map. CAD-importable (DWG/DXF) deliverables available for engineering projects.
Can GPR locate underground utilities on private property?
Yes — and this is one of our most-requested services. BC One Call covers public utilities up to the property line; everything inside the lot is your responsibility. Private-property GPR utility location is the safest way to map before excavation.
How long does a survey take?
Small concrete scan: 15–30 minutes per location. Whole-property utility survey for typical single-family lot: 2–4 hours. Large commercial sites: full day or more.
Can GPR detect rebar and post-tension cables?
Yes — one of the most common uses. 1.6 GHz antennas map the full reinforcement layout in slabs, walls, and beams. Critical before coring or drilling on post-tensioned slabs where cutting a PT cable can be catastrophic.
Related guides & services
GPR Services Hub
Slab Leak Detection Guide
Underground Service Line Guide
Buried Oil Tank Detection Guide
Compare: Acoustic vs Thermal vs GPR
Ready to talk to an expert?
Free phone consult — no pressure, no obligation. A Leak.ca technician will tell you whether you actually need detection.