Guide · Leaks and taps
How to find a water leak in your home
Start at the meter: close every tap and see whether the small wheel or star on the dial still turns. If it does, water is going somewhere, and closing the valves one at a time shows you whether it is the toilet, an appliance or a hidden pipe. If the leak is in the wall or under the floor, you need a search with instruments before breaking anything open.
1-2 hours, mostly waiting Difficulty: EasyUpdated 25 October 2026
What you need
- Torch
- Phone for photos
- Kitchen paper
- Food colouring
- Pen and paper for the readings
Step by step
Tap a step to mark it as done.
Water leak in the wall: how to recognise it
A leak from a pipe in the wall leaves a stain that always starts from the same spot, with plaster that swells and paint that peels. Sometimes, in silence, you can hear water running inside the wall. But the stain can also appear a metre from the break, because water runs along the pipe.
When it gets wet also matters. If the stain grows only after a shower or a wash and the meter stays still, the fault is probably a drain, which only leaks while water passes through. If it is always damp and the meter turns, it is a pressurised water pipe.
Before opening the wall it is worth knowing which section leaks. The valves are closed, the pipes are put under pressure one stretch at a time, and their route is mapped. That way, if something has to be broken open, it is broken once and in the right place.
Water leak under the floor
In bathrooms and kitchens the pipes often run in the screed, the layer of cement under the tiles. The clues are tiles that lift or sound hollow, swollen skirting boards, a warped parquet floor, damp at the foot of the walls even in summer. Often the first to notice is the neighbour below.
To find the exact spot, technicians divide the system into sections and then use different instruments depending on the case: a thermal camera, which shows where the water has spread; microphones that listen for the sound of the leak; or a harmless tracer gas that is detected where it escapes from the pipe. On quote websites in the Naples area, a leak search costs roughly 60 to 800 €. The range is wide because it depends on the method and the hours.
Water bill too high: what you can ask for
Before assuming a leak, check the bill: if consumption was estimated, the increase may be an adjustment. Compare the reading on the bill with the one on your meter and, if you can, send in a self-reading.
If a hidden leak exists, the ARERA regulation (resolution 609/2021) provides protection for hidden leaks. After the repair you can ask the utility to recalculate the bill. For ABC Napoli, for example, consumption must be at least double your daily average of the previous two years. The excess is billed at half the base rate, and the protection can be obtained at most once every two years.
The exact conditions and the form are in your utility's service charter. You usually need the invoice for the repair, or a declaration if you did it yourself, and a photo of the meter after the work. Keep them from day one.
When to stop and call a technician
- The meter turns with everything closed but you cannot find any wet spot in the house
- The meter turns even with the main stopcock of the house closed
- The stain is on the ceiling of the neighbour below and it is all dry at your place
- The boiler pressure drops every few days even though you have not bled the radiators
- To reach the pipe you would have to break tiles or walls without knowing where
Frequently asked questions
How do I find a water leak in a wall without breaking it open?
The meter test tells you whether the leak exists, and closing the valves one at a time tells you which section. The exact spot in the wall is found with instruments such as a thermal camera or listening equipment, before anything is opened.
How do I know if I have a water leak under the floor?
The most reliable sign is the meter turning with everything closed. Then there are the clues: tiles that move, swollen skirting boards, damp at the foot of the walls, a wet ceiling at the neighbour below.
My water bill is too high: could it be a leak?
Yes, especially if your habits have not changed. First check that the bill is not based on estimated consumption, then do the meter test at night.
What is a hidden water leak?
It is a leak in the private system, buried or in the wall, that cannot be seen from outside and is not found with ordinary attention. If consumption has risen a lot, after the repair you can ask the utility for the protection provided by ARERA.
Who looks for the leak, the utility or me?
As a rule, leaks after the meter, on the home system, must be found and repaired at the customer's expense. In Campania we can start with a pre-diagnosis on a video call, so the visit starts at the right section.
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