Finding a hidden water leak: 6 signs + our method
A leak in the wall or under the screed often goes unnoticed until damage is significant. Here is how to spot it early and how we locate it without major demolition.
A hidden leak is treacherous. No visible water, no puddles — just a bill that climbs and walls that feel oddly cool. Three out of five leak interventions we run fall in this category. Early detection saves literally thousands in follow-on damage.
Six signs of a hidden leak
- Water meter spinning while all taps are closed (classic, least noticed).
- Bill suddenly 20% higher without explanation.
- Damp patch or limescale ring on a wall, often low near the skirting.
- Loose tiles or bulging silicone in a wet room.
- Mouldy smell that lingers in a cupboard or basement corner.
- Unexplained drop in heating pressure (hot-water-side leak).
The first test you can do
Close all taps, disable WCs with stop-valves, read your meter. Wait one hour without using anything and read again. Meter moved? Leak confirmed. Did not move? The issue may be a toilet (float/mechanism) or in the heating loop.
How we locate the leak
Standard four-step approach, no unnecessary chiselling:
- Pressure test (isolate loop by loop) — confirms which loop has the leak.
- Acoustic microphone on the pipe — listens for the hiss of a pinhole under pressure.
- Thermal camera — shows damp areas through temperature contrast.
- Endoscope or inspection camera as needed — for leaks in waste or sewer pipes.
What does a leak detection cost?
A proper leak detection costs €250 – €500 depending on complexity. Sounds steep, but the alternative cost (opening a whole wall, water damage to the floor below, mould remediation) quickly runs into thousands. Our inspection is fixed-fee — no surprises after.
Suspect a leak? Do not wait. The earlier we locate it, the less damage — for your home and your wallet.
Written by
Henri Faveere
Owner Favesan
Henri Faveere has been a working plumber for over twenty years. Through Favesan he delivers plumbing, heating, AC and ventilation projects in greater Waregem and beyond.
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