Clues in the house
- Paint bubbling, peeling or staining on one wall.
- Skirting boards swelling or coming away.
- Grout cracking or tiles loosening near a shower or vanity.
- A musty smell in one room or cupboard.
- Timber floorboards cupping or lifting.
- A warm patch on a tiled or concrete floor.
Is it a water pipe at all?
Not every damp wall is a leaking pipe. A shower with failed waterproofing, a leaking waste pipe, a roof or gutter, or condensation can all look the same. The meter is the quickest way to tell: a supply pipe leaks all the time, so the meter moves with everything off, while a shower or waste pipe only leaks when it's being used.
If you suspect the shower, see shower repairs.
How a plumber narrows it down
Confirm it at the meter
With every tap and appliance off, a moving meter confirms a leak in the supply pipes.
Hot or cold?
Isolating the hot water system shows whether the leak is on the hot side. A hot pipe leaking under a slab often shows as a warm patch.
Use the right tool
A thermal camera traces hot pipes through walls and floors, a moisture meter maps a damp wall, and listening gear finds water escaping under concrete.
Open one spot
With the leak pinned down, the plumber opens a small section, repairs the pipe and pressure-tests it.
Under the house
If you have a timber floor and can safely look underneath with a torch, check for drips, wet soil, puddles, or pipe joins with green or white crust. Tell the plumber what you saw.
On a slab, a leaking pipe under the concrete is sometimes better rerouted through a wall or ceiling than dug out. Ask the plumber to compare both before the slab is broken.
Whose pipe is it?
Where your part starts is set by your water company, named on your bill. Yarra Valley Water's wording is that "All plumbing from the meter to the house are internal pipes of the property and are owned and maintained by the property owner." Check your own company's rule before you assume either way.
What changes the job
What the wall or floor is made of: plasterboard opens and patches easily, while tiles, brick and slab take longer. Hot or cold pipe, and what the pipe is made of. How long the leak has run, because the plaster, flooring or paint it damaged may need other trades after the plumber. And whether your insurer wants a written report first.
Before the plumber comes
You can
- Do the meter test before anything else.
- Take dated photos of stains and damp as they change.
- Stop using a shower you suspect until it's checked.
- If your insurer is involved, ask what it needs before any wall is opened.
Leave to a licensed plumber
- Thermal, moisture and acoustic testing.
- Opening a wall or floor and repairing the pipe.
- Rerouting a pipe that runs under a slab.
- Pressure-testing after the repair.
Licences
Repairing a pipe inside a wall is licensed plumbing work. In WA, it's an offence to knowingly engage an unlicensed person to do plumbing work, with a penalty of $5,000. Wherever you are, check the licence on your state's register first: see how to check a plumber's licence.
Questions to ask the plumber
- How will you find it, and how big an opening will you need?
- Can the pipe be rerouted instead of breaking the slab?
- Will you write down where it was and what caused it?
- Who should I call for the plaster and painting afterwards?
What we would do
Act on the first stain, not the third. A leak inside a wall keeps going whether you look at it or not, and the longer it runs, the more plaster, timber and flooring need replacing after the pipe is fixed. Do the meter test, take photos, and get a leak specialist with thermal and listening gear to find it before anyone starts cutting.