Underground storage tanks are among the most significant environmental liabilities a property can carry. A buried fuel tank that has leaked — or is actively leaking — creates a contamination problem that can cost tens of thousands of dollars to remediate, trigger regulatory action, and derail real estate transactions.
The challenge is that old tanks are often not where anyone expects them to be. They don't appear on current records. Previous owners didn't disclose them. They were abandoned in place when properties changed hands decades ago. Detecting them before they become a problem — or before you purchase a property where they already are one — is what UST detection is for.
When Is a UST Survey Required?
A UST detection survey is commonly required or strongly recommended in the following situations:
- Real estate due diligence on properties that historically housed gas stations, auto repair shops, farms, industrial facilities, or dry cleaners — all of which carry elevated risk of buried tanks
- Phase 1 Environmental Site Assessments (ESA) where historical use suggests petroleum storage
- Phase 2 ESA investigations before any drilling begins
- Tank decommissioning — confirming the exact location, boundaries, and associated infrastructure before excavation
- Insurance investigations following a petroleum release or spill
- Regulatory compliance under the BC Environmental Management Act and Contaminated Sites Regulation
How UST Detection Works
UST detection combines Ground Penetrating Radar (GPR) and Electromagnetic (EM) methods in a systematic grid survey across the area of interest.
GPR transmits radar pulses into the ground and records reflections from buried objects. Tanks create distinctive hyperbolic signatures in the GPR data — a recognizable arching pattern that indicates a subsurface void or metallic mass. GPR is effective in most soil conditions and can detect both metallic and non-metallic tanks.
EM is used to verify metallic targets and detect any associated buried fill lines, vent pipes, or electrical conduits. EM correlation with GPR anomalies increases confidence in the identification and helps distinguish tanks from other buried metallic objects.
The survey is conducted using a dense grid pattern — crossing the entire investigation area in multiple directions to minimize missed targets. Scan spacing depends on target depth and the expected size range of tanks being investigated.
What We Look For
Beyond the primary tank itself, a thorough UST survey looks for:
- Tank boundaries and estimated dimensions
- Associated product lines — fill lines, suction lines, vent pipes, and return lines
- Overfill protection devices
- Secondary containment features
- Any secondary or satellite tanks (single-wall tanks were often supplemented or replaced without full decommissioning of the original)
- Evidence of historic excavation or remediation (disturbed soil signatures in GPR data)
Finding the associated infrastructure — not just the main tank — is what separates a comprehensive UST investigation from a basic surface scan.
What You Receive After the Survey
A completed UST detection survey produces the following deliverables:
- Field markings — all detected anomalies marked on the surface with paint and/or flags, with annotated depth
- Plan drawing — a site-referenced plan showing all detected anomalies, their approximate dimensions, and depth
- Written report — a PDF documenting the survey methodology, equipment used, grid coverage, all detected anomalies, and our interpretation of findings, formatted for inclusion in a Phase 1/2 ESA, insurance investigation, or regulatory submission
Reports are delivered within 48 hours of survey completion on standard projects.
Regulations and Compliance in BC
In British Columbia, petroleum storage tanks are regulated under the BC Environmental Management Act and the Petroleum Storage and Distribution Facilities Storm Water Regulation. The BC Ministry of Environment maintains a contaminated sites registry, and UST-related contamination is a notifiable condition under the Contaminated Sites Regulation.
Prior to any tank removal or abandonment-in-place, BC regulations require site characterization. A professional GPR/EM survey is typically the first step in that characterization process and the most cost-effective way to establish what is present before committing to invasive investigation.
Next Steps After Detection
If a buried tank is detected, the next steps depend on the project context:
- For real estate transactions — the finding is documented in the ESA report and factored into negotiations or conditions of sale
- For Phase 2 ESA — the confirmed tank location informs borehole placement and soil and groundwater sampling plans
- For decommissioning — the survey results guide tank excavation and recovery operations
- For regulatory submissions — the report is included in the site record and disclosure to BC Ministry of Environment
GPR Surveys works directly with environmental consultants, real estate lawyers, and property owners throughout Vancouver Island and the Lower Mainland to ensure UST survey findings are properly documented, reported, and used effectively in the next stage of your project.