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Ground Penetrating Radar Systems (GPRS) was recently contacted to provide emergency leak detection services in Rochester, New York, for a large Target Corporation distribution warehouse. An emergency fire watch had been implemented after sections of the facility's fire protection loop were shut down due to water surfacing across multiple loading dock areas.
Emergency Leak Investigation
Steve Carney, a GPRS Subsurface Consultant, was called in to investigate the source of the leak. To accurately locate the issue, water service needed to be restored. Steve recommended operating the system at a reduced pressure level to limit further water loss while allowing testing to proceed.
Once the water system was restored to street pressure of approximately 80 PSI, acoustic leak testing began. Using specialized acoustic listening equipment, Steve tested available access points, including two hydrants and three risers throughout the facility.
The testing quickly revealed that the leak was not located on the main fire protection loop itself, but rather on a lateral line feeding the warehouse.
Narrowing Down the Leak Location
To further refine the suspected leak area, a leak detection correlator was deployed. The correlator confirmed the target area and enabled Steve to continue tracing the underground pipeline using a pipe and cable locator.
After mapping the utility route, additional surface acoustic testing was performed directly above the target pipe. Although some leak noise could be detected through the concrete loading dock surface, greater accuracy was needed.
To amplify the leak signal, a pump was used to increase system pressure from 80 PSI to 170 PSI. With the additional pressure applied, GPRS water loss specialists were able to clearly identify the leak location from the surface.
Confirming the Leak
For additional verification, a video pipe inspection camera was inserted through a building riser and directed toward the main line. During the inspection, the team observed silt entering the pipe as water drained from the system.
This visual evidence confirmed the suspected leak location.
Before excavation began, surrounding underground utilities were identified using pipe and cable locating technology. The planned excavation area was found to be positioned between a 4-inch gas main and an electrical duct bank, making accurate utility locating critical to safe excavation.
Excavation Reveals a Hidden Hazard
After utility locations were verified using a vacuum truck, excavation work commenced. As crews saw-cut and jackhammered through the concrete surface, they discovered a significant void beneath the slab.
The finding was particularly alarming because a fully loaded tractor trailer had reportedly been parked in the exact location the night before.
As excavation continued, the water main was exposed approximately 12 feet below grade. The source of the leak was identified as a deteriorated mechanical joint that had completely rotted out.
Findings and Recommendations
Following the repair, the customer was informed that similar failures could occur elsewhere in the system. The investigation revealed no supporting rock material above or below the failed joint, which may have contributed to the failure. In addition, long-term exposure to corrosive soil conditions may have accelerated deterioration of the joint hardware.
A Complete Subsurface Solution
GPRS provides a wide range of subsurface infrastructure services tailored to client needs, including:
- Emergency leak detection
- Pipeline pressure failure investigations
- Full-system leak surveys
- Utility locating and mapping
- Video pipe inspections
- Underground utility coordination
Whether responding to emergency water loss events or supporting ongoing infrastructure management, GPRS delivers the data needed to keep facilities safe, operational, and informed.
Note: GPRS does not provide geophysical, geological, land surveying, or engineering services. If you require these services, please contact a qualified professional.
