Hot Water System Leak Detection in North Walsham

Symptoms

At a property in NR28, water had been observed rising up through the kitchen floor, with rising damp visible along the walls and damage to the skirting boards. The hot water supply had already been isolated at the airing cupboard, yet the hot water tank was draining down rapidly — pointing to an active leak on the hot water pipework beneath the kitchen.

Electric underfloor heating in the same area was also affected.

The kitchen has a tiled floor laid over a concrete screed, with pipework running beneath it. The combination of surface water, damp walls, and a fast-depleting hot water supply made it clear that hot water leak detection was needed to pinpoint the fault before any floor break-up could begin.

The absence of any protective covering on the pipework under the screed is consistent with this type of failure. As hot pipes expand and contract with temperature changes, direct contact with concrete gradually wears through the pipe wall — eventually leading to a breach.

Methods Used

The investigation began with a pressure test on the already-isolated hot water pipework. Compressed air was introduced at the hot pipe under the kitchen sink, and the immediate pressure drop confirmed a leak was present.

Tracer gas was then introduced into the hot water pipe, and a signal was detected in the floor area in front of the sink. To refine the exact location before breaking ground, compressed air mixed with water was used alongside acoustic equipment to narrow down the precise point to begin excavation.

This multi-method approach — pressure testing to confirm a leak, tracer gas to identify the general zone, and acoustics to pinpoint the break-out area — is standard practice in hot water leak detection where the pipework is concealed beneath a concrete screed. Once the floor was opened up, one leak was found and repaired, but a subsequent pressure test revealed a second leak in close proximity, which was also addressed.

Investigation Process

1. 1
   Hot water pipework isolated

   The hot water supply had already been isolated at the airing cupboard prior to the engineer's arrival, with the tank noted to be depleting quickly.

2. 2
   Pressure test confirms leak

   Compressed air was introduced into the hot water pipe at the kitchen sink. The pressure dropped immediately, confirming an active leak in the pipework beneath the kitchen floor.

3. 3
   Tracer gas identifies zone

   Tracer gas was introduced into the hot water pipe. A signal was detected in the kitchen floor area directly in front of the sink.

4. 4
   Acoustics used to pinpoint break-out area

   Compressed air mixed with water was used alongside acoustic equipment to narrow down the precise location, identifying where the floor should be broken up.

5. 5
   First leak found and repaired

   The tiled floor and concrete screed were broken up in the identified area. One leak was located, the pipework was drained, and a new section of copper pipe was soldered in place.

6. 6
   Second leak discovered

   A pressure test following the first repair revealed a second leak in close proximity to the first. This was also repaired as part of the same visit.

7. 7
   Final pressure test passed

   After both repairs were completed, the pipework was tested at two bar of pressure. The pressure held, confirming the repairs were sound.

Result & Outcome

Two leaks were found in the hot water pipework beneath the kitchen floor, both located in the area in front of the sink. The first was identified through tracer gas and acoustic methods; the second was only revealed by a pressure test carried out after the first repair — highlighting the value of re-testing before closing up the floor. Both leaks were repaired using copper pipe and fittings, with a soldered new section installed and confirmed sound at two bar.

The root cause was the absence of any protective covering on the pipework where it passes through the concrete screed. Repeated thermal expansion and contraction of the hot pipe against the concrete had gradually worn through the pipe wall — a failure mode that hot water leak detection is specifically designed to locate without unnecessary floor damage.

The customer has been advised that the affected area will need time to dry out and that the electric underfloor heating is likely to require replacement. If the flooring is being removed as part of the reinstatement work, it is recommended that all pipework in the area is replaced and protected with insulation before the screed is relaid, to prevent the same failure recurring.