Internal Cold Mains Leak Detection in Aylesbury

Symptoms

An initial meter test on arrival confirmed a leak rate of 18 litres per hour, establishing that water was being lost continuously from the supply system. The task was a full internal leak detection to trace the source of that loss and identify the pipe involved.

Adding complexity to the investigation was the property's history: an extension had been built onto the rear of the house at some point, which had altered the original layout. This meant the incoming mains pipework had been rerouted, and the current stopcock position did not reflect the original plumbing configuration — a factor that shaped where the leak was ultimately found.

Methods Used

The investigation began at the internal stopcock in the utility room, where the acoustic signal was already apparent. Once the insulation around the incoming mains was removed, it became clear that the stopcock was being fed by a 15 mm copper pipe — confirming the supply had been rerouted when the rear extension was constructed.

The original sink location was assessed to have been where the current utility room door now sits, and this area became the focus of further investigation.

Acoustic correlation was used to pinpoint the leak position within this zone. Internal leak detection of this kind, where pipe routes have been altered by building work, requires methodical tracing rather than assumption — the acoustic equipment allowed the signal to be followed precisely to a point under the floor.

Vinyl flooring tiles and screed were then excavated at that location to expose the buried 15 mm copper pipe and confirm the leak.

Investigation Process

1. 1
   Initial meter test

   On arrival, a flow meter test was carried out on the supply. This confirmed an active leak at a rate of 18 litres per hour.

2. 2
   Acoustic signal identified at stopcock

   A strong acoustic signal was detected at the internal stopcock in the utility room, consistent with the customer's prior observation. This confirmed the leak was in the vicinity of the incoming mains.

3. 3
   Insulation removed, pipework examined

   Insulation around the incoming mains was stripped back. The stopcock was found to be fed by a 15 mm copper pipe, indicating the supply had been rerouted during a previous rear extension.

4. 4
   Original pipe route assessed

   The original sink location was assessed to be where the current utility room doorway now stands. This area was identified as the most likely leak zone based on the rerouted pipe run.

5. 5
   Acoustic correlation to precise point

   Acoustic correlation equipment was used to follow the signal to a specific point beneath the utility room floor in the doorway area.

6. 6
   Floor excavated

   Vinyl flooring tiles and screed were excavated at the identified location, exposing the 15 mm copper pipe embedded in the screed.

7. 7
   Leak confirmed and pipe repaired

   A leak was found on the buried copper pipe. A short section of 15 mm copper pipe was replaced to effect the repair.

8. 8
   System retested

   Following the repair, the system was monitored on the meter for 20 minutes with no movement recorded, confirming the leak had been resolved.

Result & Outcome

A short section of the copper pipe was replaced, and the system was retested for 20 minutes on the meter. No further movement was recorded, confirming the repair was complete and the supply was holding pressure correctly.

For internal leak detection cases where building work has altered the original pipe layout, this result demonstrates the value of acoustic tracing over assumption-based excavation. The recommendation going forward is that the floor in the affected area is thoroughly dried to prevent ongoing moisture damage to any remaining copper pipework still embedded in the screed.