Underground Water Mains Leak Detection in Chiswell Green

Symptoms

At a property in AL1, the external water meter was observed to be continuously moving, registering a high volume of flow even when no water was in use anywhere in the building. This is a clear indication of an active leak on the underground supply pipework between the meter and the property.

The underground mains runs from the water meter set into the concrete driveway, continues beneath an extension at the side of the property, and feeds through to the kitchen at the rear.

Because the pipework runs underground and passes beneath concrete and built structures, the leak point could not be identified visually without further investigation. A water mains leak detection survey was required to trace the route and pinpoint the exact location before any excavation could take place.

Left unaddressed, a leak of this nature results in ongoing water loss, potential damage to surrounding ground and structures, and continued charges for water that is never used. Identifying the precise leak location before breaking ground was essential to minimise unnecessary disruption.

Methods Used

The investigation began by confirming the meter behaviour on arrival — the meter was clearly letting water by at a high volume with no consumption taking place. The underground pipework route was established: from the meter on the concrete driveway, beneath the side extension, and on to the kitchen.

Because the pipe runs under concrete and a built extension, a water mains leak detection approach using tracer gas was selected to locate the leak without unnecessary excavation across the full run.

Trace gas was introduced into the pipework and detection equipment was used to track where gas was escaping at ground level. This narrowed the leak to the area around the front of the garage.

Acoustic equipment was then deployed to confirm the precise point, identifying the leak as being under the concrete directly in front of the garage. The area was excavated and the leak was visually confirmed — the pipework had been physically damaged by the concrete bearing down on it.

Investigation Process

1. 1
   Meter behaviour confirmed

   On arrival, the external water meter was observed running continuously at high volume with no water in use inside the property, confirming an active underground leak.

2. 2
   Pipework route established

   The underground supply route was traced from the meter on the concrete driveway, beneath the side extension, and through to the kitchen at the rear of the property.

3. 3
   Tracer gas introduced

   Trace gas was introduced into the pipework and detection equipment was used along the route, identifying the escape point as being in the area around the front of the garage.

4. 4
   Acoustic equipment deployed

   Acoustic correlation was used to confirm the precise leak location, pinpointing it to under the concrete surface directly in front of the garage.

5. 5
   Area excavated and leak exposed

   The concrete was broken out and the area excavated to expose the pipework. The leak was visually confirmed — the pipe had been damaged by the concrete.

6. 6
   Pipework repaired

   A new section of pipework was installed with new fittings to replace the damaged section.

7. 7
   Repair verified

   The water meter was observed to have stopped moving, and a pressure test confirmed no further leaks were present on the pipework.

8. 8
   Area reinstated

   The excavation was backfilled and the surface levelled using the broken concrete.

Result & Outcome

The leak was located under the concrete directly in front of the garage, where the underground supply pipework had been damaged by the concrete bearing down on it. Tracer gas identified the zone and acoustic correlation confirmed the precise point, meaning only a targeted excavation was required rather than breaking out the full driveway or the area beneath the extension.

A new section of pipework was installed with new fittings to replace the damaged pipe. Once the repair was complete, the water meter was stationary — no longer registering any flow — and a pressure test confirmed the system was holding with no further leaks present.

For water mains leak detection jobs of this type, where pipework runs beneath concrete and built structures, the combination of tracer gas and acoustic methods is what makes it possible to pinpoint the fault before any ground is opened up. The area was backfilled and levelled with the broken concrete, leaving the repair complete at the point of visit.