Underground Water Mains Leak Detection in Carlisle

Symptoms

With a running meter and no surface evidence, a water mains leak detection survey was the only reliable way to confirm and locate the fault. The absence of visible indicators pointed to an underground leak, likely along the external mains supply serving the farm.

Methods Used

Water mains leak detection in rural and farm settings often presents challenges that require multiple methods before a clear result is achieved. The combination of acoustic, pressure, and tracer gas techniques on this job reflected the difficulty of working without surface indicators and with multiple water-fed assets on site.

During the inspection, it was also noted that one of the farm troughs was passing, and two troughs were found to have no isolation valves, which limited the accuracy of retesting.

Investigation Process

1. 1
   Initial Assessment

   The meter was observed continuing to spin with the stopcock isolated, confirming water loss through the system. No surface signs of leakage were present, ruling out a straightforward visual location.

2. 2
   Acoustic Survey

   Acoustic correlation equipment was deployed to trace the suspected leak along the external pipework. No clear results were obtained from the acoustic survey.

3. 3
   Pressure and Tracer Gas Testing

   A pressure test was carried out, and tracer gas was introduced into the pipe. A positive result was returned at the rear of the property, focusing the investigation on that area.

4. 4
   Excavation

   With the customer's permission, the area at the rear of the property was excavated. The customer assisted using his own digger, exposing the pipework for direct inspection.

5. 5
   Leak Identified and Repaired

   Once exposed, the leak was confirmed as being caused by an installation fault. The damaged section of pipe was cut back and a new section was installed to restore supply integrity.

6. 6
   Additional Findings Noted

   During the inspection, one of the farm troughs was found to be passing, and two troughs were identified as lacking isolation valves. The customer was advised accordingly.

Result & Outcome

In addition to the mains repair, the customer was advised to have both farm troughs inspected for potential faults and, if necessary, to have the ball valves replaced. It was also recommended that isolation valves be fitted to each trough to allow for more efficient operation and easier maintenance going forward.