Water leak detection for pipes in walls, floors and ceilings
Water leak detection pinpoints a leaking hot or cold water pipe that runs out of sight in a home, whether it is buried in a wall, laid under a floor or carried above a ceiling, and marks the point where it can be reached. West Country Leak Detection traces these leaks in homes across South West England.
Where do water pipes leak inside a home without showing it?
Water pipes leak inside a home without showing it wherever they run out of sight: inside walls, under floors and in the space above a ceiling, as with the shower supply pipe found leaking above a kitchen ceiling in one ombudsman case.
- Inside a wall: brown stains or damp patches are usually the first signs you will see, according to Aviva, and the NRLA adds peeling paint and bubbling wallpaper.
- Under a floor: water stains can appear on floors as well as walls and ceilings, the NRLA tells tenants, and in ombudsman decision DRN-5382026 the leak sat on a water pipe beneath a kitchen floor.
- Above a ceiling: in decision DRN-4125471 of the Financial Ombudsman Service, a stain on a kitchen ceiling turned out to come from the shower supply pipe in the bathroom above.
The stain is not necessarily the place where the pipe leaks: in that ombudsman case the kitchen ceiling stained while the leaking pipe ran through the bathroom above it. A damp patch is a clue to where the search starts, and never a map of the pipe itself.
Which signs point to a leaking hot or cold water pipe?
The signs that point to a leaking hot or cold water pipe are damp patches or brown staining on walls and ceilings, peeling paint or bubbling wallpaper, a musty smell or mould, dripping or running water you can hear with every tap off, and lower water pressure.
Each sign below is listed by the organisation that names it.
- Brown stains or damp patches on walls and ceilings, which Aviva calls usually the first signs of a leak that you will see.
- Discolouration, peeling paint or bubbling wallpaper, the forms a water stain may take in the NRLA's advice to tenants.
- A musty smell, or mould growing on internal walls or ceilings, which Aviva says a hidden pipe leak may be behind.
- Running water you can hear with every tap turned off (Aviva), dripping sounds (the NRLA), or a hiss or knock near the internal stop tap (Wessex Water).
- Lower water pressure, which Aviva lists, Wessex Water describes as a big drop, and WaterSafe ties to a leaking supply pipe when it shows at the kitchen tap.
A stain on a ceiling below a bathroom is one example of the first sign, from the ombudsman case in the section above, and no rule says it always starts there. Lower pressure and a hiss at the stop tap can also come from the supply pipe outside, which is why the next check matters.
How can you tell an indoor leak from a leak on the supply pipe outside?
You can tell an indoor leak from a supply pipe leak with the meter and the internal stop tap: with no water in use and the internal stop tap closed, a dial that keeps moving points to a leak outside, and a dial that stops points to a leak inside, according to Wessex Water.
The internal stop tap is the tap that shuts off the water to the home (insurers such as Admiral call it the stopcock), and South West Water and Bournemouth Water say it is usually under the kitchen sink. Wessex Water's metered test runs in three steps.
Stop all water use in the home
Turn off the taps and every water-using appliance, so that no water should be passing through the meter.
Read the water meter dial
Watch the dial with everything off. If it is still turning, Wessex Water says there is most likely a leak.
Close the internal stop tap and read the dial again
A dial that carries on moving points to a leak outside the property, most likely on the supply pipe. A dial that stops points to a leak inside.
Bristol Water reads the same test its own way: a dial that moves after you isolate the internal stop tap could mean a leak between the meter and that tap, and a dial that stops means the leak must be inside after it. South West Water asks for no water use for an hour, a reading of every dial including the red numbers, a second reading an hour later, then the same test with the internal stop tap off.
Homes without a meter use Wessex Water's listening test instead. Turn off the appliances, put an ear to the internal stop tap for a hiss or knock, then close it and listen again. Wessex Water reads a sound that continues as a leak most likely outside, and a sound that stops as one most likely inside.
A leak that the test places outside lies on the buried supply pipe, which is where underground water leak detection takes over.
Which methods trace a water pipe leak in walls, floors and ceilings?
Acoustic listening, thermal imaging, moisture mapping and pressure testing trace a water pipe leak in walls, floors and ceilings, and tracer gas is used where a pipe is quiet or not under pressure.
| Method | What it detects | Its limit |
|---|---|---|
| Acoustic listening | The sound of escaping water on a pipe that holds pressure. | With no pressure in the pipe, or no sound from the leak, there is nothing to hear, and Sewerin's advice in that case is tracer gas. |
| Thermal imaging | Warm or cool areas on a surface caused by leaking hot water, heating water or damp. | The camera sees surfaces only, so it cannot read through a wall, floor or slab, and without a temperature difference it shows nothing; any patch it picks up is checked another way, because a draught can also make a cold patch, and Fluke notes it narrows the search area, so some plaster or paving may still have to be broken. |
| Moisture mapping | Which parts of a wall, floor or ceiling hold more moisture than the rest. | Its readings compare one spot with another: meters set up for timber cannot measure stone, brick or plaster reliably, salts and metal near the surface affect them, and a map shows the wetter areas without giving a true moisture content. |
| Pressure testing | Whether a system, or one part of it, is losing water. | A gauge can fall without a leak, because plastic pipe stretches under pressure and air trapped in the system has to be bled out first. |
| Tracer gas | Hydrogen rising out of the leak through a floor, a drive or the ground. | How quickly the gas surfaces depends a great deal on the ground above the pipe, INFICON says, so no time is ever promised. |
No single method sees everything. A thermal camera cannot look through a wall or concrete, Teledyne FLIR explains, so a cold pipe buried in plaster may show nothing at all, and a moisture map shows where a surface is wetter without giving a true moisture content.
That is why one method is checked against another before plaster or paving is broken.
Who arranges the repair when water comes through from the flat above?
The owner of the flat above arranges the repair of a leak on that flat's own pipes, or the landlord where it is rented, while a leak on a supply pipe shared by several flats is the joint responsibility of every owner it serves.
When the leak is on the pipes inside the flat above
Pipes and fittings inside a home, appliances included, are the owner's responsibility, Wessex Water says. Water coming through your ceiling from one of those pipes is a repair for the owner of the flat above.
When the leak is on a supply pipe shared by several flats
A supply pipe shared by several properties is the joint responsibility of every owner connected to it, according to the Consumer Council for Water. South West Water puts it the same way for flats: where the supply pipe is shared, so is the responsibility for looking after it.
When the flat above is rented
A landlord on a short residential lease must keep the water installations in repair and in proper working order, under section 11 of the Landlord and Tenant Act 1985, and GOV.UK names pipes among the repairs a landlord is always responsible for. Wessex Water tells tenants to let the landlord know about a leak as soon as possible and to check the tenancy agreement.
Who pays for the damage below is a question for the insurers and the owners, and this page does not settle it. Tell your own insurer what you have seen, with photographs, and read how trace and access for an escape of water claim works before any plaster or paving has to be broken.
What happens after the leaking pipe is located?
After the leaking pipe is located, its position is marked on the wall, floor or ceiling, and the findings record where the leak is and what access is needed to reach it, which is what insurers ask trace and access specialists to report.
West Country Leak Detection traces the leak and marks it; the repair itself is arranged separately. Insurer and comparison guides, Confused.com among them, name the findings that matter: where the leak is, the access work that reaching it will take, photographs, and the cause if it can be established.
Keep your own photographs too. Aviva, Admiral, NFU Mutual and MoneySuperMarket all ask for pictures when a claim is made, and MoneySuperMarket asks for the leak and the area around it.
One limit applies before you call your water company: South West Water's code of practice says it does not get involved with a leak inside the home and gives no leak allowance for one. If an insurer is involved, read how insurers pay to trace a leak.
Where else on a property can a hidden leak be traced?
Elsewhere on a property, a hidden leak can be traced on the central heating, on the buried supply pipe running from the boundary to the house, and for an insurer that needs the source of escaping water found.
- A boiler that keeps needing to be topped up points to the sealed heating circuit, which central heating leak detection traces, testing underfloor heating loop by loop.
- With the internal stop tap closed, a meter dial that keeps moving sends the search outside, to tracing a buried supply pipe leak between the boundary and the house.
- Where an insurer asks for the source to be traced before the claim proceeds, the search may fall under trace and access cover for a claim.
Every investigation is set out together under leak detection across the South West.