A hidden water leak usually progresses quietly. If the pipe is inside a wall or under the floor, by the time the water becomes visible the damage may already be done. That is why it pays to recognise the signs early and confirm any suspicion with a simple meter test. For villa owners whose house stands empty for long periods, this test is the most practical check there is, and someone can even do it for you while you are away.
Common signs of a hidden leak
- Your bill has gone up unexpectedly. Higher consumption with no change in use is the first warning.
- Stains on walls or ceilings. Look for bubbling paint, crumbling plaster or yellowing around the edges.
- A musty smell or mould. Especially in bathrooms, kitchens and behind cupboards.
- The sound of running water. Flowing or hissing in the pipes when every tap is off.
- A warm patch on the floor. If a hot water pipe runs under the floor, a leak can create a warm spot.
- Lower water pressure. Taps running weaker than they used to.
- The booster pump starts on its own. If the pump kicks in at short intervals while nobody is using water, water may be escaping somewhere in the system.
- A patch of garden that never dries. Grass or mud that stays wet with no rain can point to a leak in an underground pipe.
How to do a meter test
This is the simplest way to find out whether there is a leak in the house. You don't need any special tools.
- Turn off all water use. Make sure no water is being used anywhere: taps, showers, washing machine, dishwasher, irrigation system and pool top-up included. Wait for the toilet cisterns to finish filling.
- Note the meter reading. Take a photo of the numbers. Many meters also have a small rotating indicator (a wheel or star) that shows even very small flows.
- Wait. Use no water at all during this time. The longer you wait, the easier it is to spot a small leak.
- Check again. If the reading has changed or the indicator is turning, water is escaping somewhere after the meter.
If the house has a main stopcock after the meter, repeat the test with that stopcock closed. If the meter still moves with it closed, the leak is on the line between the meter and the stopcock, which often means a pipe under the garden. If the meter stops, the leak is inside the house.
The cistern: the most commonly missed leak
A faulty float valve or seal in a toilet cistern lets water trickle silently into the bowl. It usually doesn't wet any walls, but it pushes up your bill. To check, put a few drops of food colouring in the cistern and wait for a while without flushing. If colour appears in the bowl, the cistern is leaking. This is usually fixed by replacing a part.
What to do if there is a leak
- Close the main stopcock and, if necessary, switch off the booster pump.
- Be careful with electricity in wet areas. If water has reached a socket, junction box or wiring, switch off that circuit at the fuse box and do not touch the wet area.
- Take photos. Record the meter, the stains and the damage with dated photos; you may need them for an insurance claim.
- Don't break open walls on a guess. Knocking holes in walls or floors at random adds cost and stretches out the repair.
When is leak detection equipment needed?
If the location of the leak is unclear, methods such as acoustic listening, thermal imaging or pressure testing can narrow it down without breaking anything open. This usually means only the leak point itself has to be opened up. It is especially useful for underfloor heating, pipes buried in walls and lines under the garden.
Frequently asked questions
How long should the meter test last? There is no fixed time; the longer you wait, the easier small leaks are to see. A test done while nobody is home, for example overnight, gives the most reliable result.
If there is no leak, will the meter stay completely still? If no water is being used and the system has no leak, the meter should not move. A refilling cistern, an automatic pool top-up or an irrigation timer left on can give a misleading result.
How can I keep an eye on this while the house is empty? Photographing the meter on the same day each month is a simple but effective method. This check is part of the Home Care Plan visits. For other regular checks, see the villa care checklist for owners living abroad.
For leak detection and repairs, see the plumbing page.
This guide is for general information. Every home is different; for your own home, ask a company that has seen the work on site for a written quotation.