Underground Water Mains Leak Detection in Banbury

Symptoms

The meter was registering flow at a rate of 1 litre per minute with all internal fittings off. Underground leaks of this type can persist undetected for extended periods, as there is no visible sign of water at the surface.

The priority was to isolate which section of pipework was responsible and then pinpoint the precise leak location without unnecessary excavation.

Methods Used

The investigation began with sectional isolation, closing the internal stopcock in the kitchen to determine whether the leak was inside or outside the building. With the meter continuing to flow after isolation, the leak was confirmed on the underground supply between the meter and the stopcock.

Tracer gas was then introduced into the pipework, and acoustic listening equipment was used to track the gas escaping at the defect point. This located the leak beneath a pathway at the side of the property.

In water mains leak detection involving buried supplies, this combination of techniques allows precise location without speculative digging.

Investigation Process

1. 1
   Meter flow confirmed

   On arrival, the external water meter at the entrance to the driveway was inspected and found to be passing water at a steady rate of 1 litre per minute with no water in use at the property.

2. 2
   Internal stopcock isolated

   The internal stopcock, located in the kitchen at the rear of the property, was closed. The meter continued to flow, confirming the leak was on the underground pipework between the meter and the stopcock.

3. 3
   Tracer gas introduced

   Tracer gas was introduced into the underground pipework to allow the leak point to be located without excavating the full run.

4. 4
   Leak located beneath side pathway

   Using acoustic listening equipment to track the escaping gas, the leak was traced to a point beneath a pathway at the side of the property, where leaking noise could also be heard.

5. 5
   Area excavated and leak identified

   The pathway was opened up at the identified location, exposing a transition joint where old pipework connected to new pipework — this joint was the source of the leak.

6. 6
   Joint replaced and area reinstated

   The defective transition joint was removed, new seals were installed, and the excavated area was backfilled.

7. 7
   Customer advised on pipework

   The customer was informed that the underground black poly pipe was an unusual size, which is relevant for any future work on the supply.

Result & Outcome

The customer was also advised that the underground black poly supply pipe was an unusual size. This is worth noting for any future maintenance or repair work on the supply, as standard fittings may not be suitable.