The first thing is to shut off the main water valve of the home. It does not matter whether it is a drip or a jet: as long as the installation is under pressure, water keeps coming out. Then move water away from sockets and appliances, and take photos before cleaning anything. The remaining steps, in the order in which it is best to take them, are set out below.
1. Shut off the main valve
In a flat it is usually under the sink, in the bathroom behind an access panel, or near the front door; in buildings with a bank of meters there is also a valve in the building's meter room. In a detached house it is almost always in a box on the pavement or next to the façade, and sometimes a square key is needed to open it. If the valve is stiff because of limescale, do not force it with a long tool: it can break. Turn it by hand as far as it will go.
If you cannot find it, close the meter valve. And if the water is coming through the ceiling, the leak is not in your installation: the valve to close is that of the neighbour upstairs or the community's (see step 5).
2. Decide whether to cut the power
Cut the electricity at the consumer unit if the water has reached sockets, power strips, appliances, the consumer unit itself or recessed lights in a ceiling that is dripping, or if the RCD has tripped. If the leak is small and localised and there is no electrical installation nearby, it is not necessary. Never touch the consumer unit with wet hands or barefoot on a damp floor.
3. Contain the water
- Place buckets under the drips: even after you have closed the valve, the pipe keeps draining for a while.
- Remove rugs and objects from the wet floor; parquet and laminate swell within hours.
- If the ceiling is holding water (a bulge in the plaster or a panel that sags), do not stand underneath or try to drain it yourself: cut the power in that area if there are light points or wiring nearby, clear what is underneath, and call a professional.
- Do not use a domestic vacuum cleaner to pick up water. Do not switch on underfloor heating "to dry things out": if the leak is in the heating circuit itself, you will make it worse.
4. Take photos and a video before cleaning
Photograph the exit point if it is visible, each damaged area, the level the water has reached and the meter. Record a short video walking through the rooms. The date is recorded in the phone's files and will serve as documentation if you report the claim to your insurer. Clean up only afterwards.
5. Alert whoever is responsible
- If the water comes from above, tell the neighbour: many concealed leaks show no symptoms in the flat where they occur, only in the one below. If they are not at home, call the managing agent or the president of the homeowners' association. And do not assume whose leak it is: in a homeowners' community in the Region of Murcia, the damp in the flat below pointed to the one above, and the leak was indeed under its hallway, but in the pipe that supplies the neighbouring home.
- If the leak comes from your home and affects another dwelling, inform the affected neighbour and report it to your insurer.
- If it appears to be in a common element (downpipe, riser, main pipe before your valve), report it to the managing agent of the homeowners' association as soon as possible.
6. Report it to your insurer
Do it as soon as possible, ideally the same day, by phone or through the insurer's app, with your policy number, a brief description and the photos. What is covered depends on your policy: check whether it includes water damage and the search for and location of the leak, and with what limits.
7. Check whether the loss continues
Once the emergency is under control, the question is whether the leak is a one-off (a burst seal that is already visible) or a hidden loss that is still going on. The simplest check is the meter:
- Close all taps and make sure no cistern, washing machine, boiler or irrigation system is drawing water.
- Open the main valve and look at the meter. The small dial or the last digit should not move.
- If it moves with everything closed, there is a loss in your installation. Note the reading, wait one hour without using any water and note it again: the difference is what you lose per hour.
Two further clues help narrow it down: if you have separate hot and cold water valves, close one and see whether the meter stops; and if the home has heating or underfloor heating, a boiler pressure gauge that drops and forces you to top up the circuit points to a leak in the heating, not in the domestic water supply.
8. Locate before repairing
The most expensive mistake is to break open where the stain appears. Water travels inside floor slabs and walls and surfaces far from the exit point, so opening "where you can see it" often ends in two or three exploratory openings without finding anything. Concealed leaks are located from the outside with section-by-section pressure tests and listening equipment, tracer gas or a camera depending on the pipe, and only then is the wall opened at the indicated point. We explain when each technique is used in the comparison of leak detection techniques without construction work.
What information speeds up the diagnosis
When you call a leak detection company, having this to hand lets them bring the right equipment and start on the correct section:
- Whether the meter moves with everything closed, and how much it shows per hour.
- Where and since when the damp has appeared, and whether it is growing or staying the same.
- Whether the stain feels warm or cold to the touch (this points to hot water, cold water or heating).
- Whether the boiler is losing pressure.
- Type of home, age and pipe material if you know it (copper, iron, multilayer, polyethylene).
- Plans or photos of the renovation, if they exist.
- For pools: type of basin and how many millimetres it drops per day, better still if you have done the bucket test.
Mistakes that make the problem worse
- Cleaning before photographing.
- Waiting days to report the claim to your insurer.
- Breaking into walls or floors to look for the leak by eye.
- Covering the damp with paint before the area has fully dried: the mould comes back.
- Considering the leak solved without checking the meter again. At a home in the province of Alicante we repaired a real leak in the irrigation system and, even so, the meter kept showing a consumption that did not match it, and the recommendation was to check the meter itself.
When it is truly urgent
It is urgent if water is coming out uncontrollably and you cannot shut it off, if it has reached the electrical installation, if it affects another dwelling or if the ceiling is holding water. In those cases, shut off the supply, inform your insurer and the community, and request detection as soon as possible. If you have managed to close the valve and the dripping has stopped, it is no longer an emergency: you have time to document things properly and to have the leak located before opening anything. For a concealed loss in a pressurised installation, you can contact us about your case through our water leak detection.
