Hot Water System Leak Detection in March

Symptoms

The occupants of a property in PE13 noticed their water meter was recording continuous usage of approximately 5–7 litres per hour, even when no water was being used inside. This pointed to an active leak somewhere in the internal pipework, though its exact location was unknown at the time of booking.

The water meter reading gave no indication of whether the leak was on the cold or hot water supply, or where in the property it might be occurring. The customer contacted us to carry out hot water leak detection and establish the source before further damage could develop.

Visually, there was no obvious sign of a burst pipe or surface water. The hidden nature of the leak made specialist detection equipment essential to pinpoint the fault without unnecessary disruption to the property.

Methods Used

The investigation began with a meter observation to confirm active usage, followed by isolation of the internal stopcock to determine whether the leak was on the internal or external supply. Once confirmed as internal, pressure testing was used to isolate the fault to the hot water pipework.

From there, moisture readings were taken to identify areas of elevated damp, and tracer gas was introduced into the hot pipes to pinpoint the precise location of the escape.

This combination of methods is standard practice in hot water leak detection where the leak is concealed beneath a floor with no visible surface indication. Each stage narrowed the search area before any invasive work was carried out, ensuring the customer could give informed consent before any lifting or cutting began.

Investigation Process

1. 1
   Meter Observation

   With all pipework live, the water meter was observed and confirmed to be recording usage. Closing the internal stopcock stopped the meter recording, confirming the leak was on the internal pipework.

2. 2
   Pressure Testing — Cold Circuit

   The internal cold pipework was pressure tested and found to be sound, with no measurable pressure loss.

3. 3
   Pressure Testing — Hot Circuit

   Pressure testing of the hot water pipes showed a loss of pressure, confirming the leak was on the hot water supply.

4. 4
   Moisture Meter Survey

   A moisture meter was used across the utility room floor and the wall at low level behind the washing machine. High wet readings were recorded in both areas, focusing the search on that zone.

5. 5
   Tracer Gas Introduction

   An air compressor was used to clear water from the hot pipes before tracer gas was added. A gas analyser tracked the escaping gas to the floor to the left of the washing machine.

6. 6
   Customer Consent and Invasive Investigation

   The gas and moisture evidence was presented to the customer and consent was given to carry out invasive work. The floor was opened in the identified area to trace the leak.

7. 7
   Leaks Located

   Two leaks were found approximately 6 inches apart in the floor beneath the washing machine. Further testing revealed a third leak approximately 10 inches from the first two.

8. 8
   Pipework Repaired

   All three leak points were cut out and the remaining pipework tested to confirm no further leaks. A section of pipe approximately 2 feet long was replaced with copper tube and soldered copper fittings.

9. 9
   Final Pressure Test

   The water supply was re-established and a mains pressure test was carried out at 3.2 bar. Pressure held with no measurable loss over a 30-minute test period, confirming the repair was sound.

Result & Outcome

Three leaks were located in the hot water pipework beneath the utility room floor, directly under the washing machine. Two were found approximately 6 inches apart, with a third a further 10 inches away. The combination of moisture meter readings and tracer gas detection identified the area precisely before any floor was opened, limiting disruption to the confirmed fault zone.

All three leak points were cut out and a section of pipe approximately 2 feet long was replaced using copper tube and soldered copper fittings. The repair was tested at mains pressure — 3.2 bar held with no measurable loss over 30 minutes — confirming the integrity of the new pipework.

This is a typical result for hot water leak detection where the leak is concealed beneath a solid floor with no surface evidence. The customer was advised to seek professional guidance on drying out the affected area, as residual moisture in the floor and wall structure will require managed drying before reinstatement.