A hidden water leak can quietly damage your home for weeks or months before you notice anything. The good news is that you can run a simple check yourself using your water meter. It takes a few minutes and costs nothing.

How to do a water meter leak test

  1. Turn off everything that uses water. Close all taps, make sure no one is showering or flushing, and switch off the dishwasher and washing machine. Check that toilet cisterns aren’t refilling and that irrigation systems and any automatic water features are off.
  2. Find your water meter. It’s usually near the front boundary, in a small in-ground box with a lid. Be careful lifting the lid, as insects and spiders like these boxes.
  3. Read the meter. Write down the numbers, or take a clear photo. Many meters also have a small dial or triangle that spins when water is flowing. If it’s moving with everything off, water is going somewhere.
  4. Wait. Leave all water off for at least 30 minutes, or longer if you can, such as while you’re out or overnight.
  5. Read it again. If the numbers have changed, or the dial is still turning, you likely have a leak somewhere on the property.

A tip: a slow leak might not move the numbers much in half an hour, so an overnight test can be more telling. Also remember that a leaking toilet or a dripping tap can be the cause, so check the obvious fixtures first.

Signs of a hidden leak

Even without a meter test, your home can give you clues:

  • Damp patches on walls, ceilings or floors that don’t dry out
  • A musty or mouldy smell, especially in cupboards, bathrooms or under floors
  • Cracked, loose or lifting tiles, or a bouncy feel underfoot
  • Peeling paint or bubbling plaster
  • Higher water bills with no change in how you use water
  • Pooling water or unusually soft, green patches in the yard, particularly in dry weather
  • The sound of running water when everything is turned off

How plumbers find leaks

Leaks in walls, slabs and underground are hard to find by guesswork, and breaking into walls or floors to look for them can cause more damage than the leak itself. Licensed plumbers use specialised, non-invasive methods to pinpoint the problem first:

  • Pressure testing to confirm whether a section of pipe is losing pressure and so has a leak
  • Acoustic or sounder equipment that picks up the sound of water escaping from a pipe
  • Thermal imaging to spot temperature differences that can show moisture or a leaking hot water line behind a surface
  • Tracer gas, where a harmless gas is introduced into the pipes and detected where it escapes, which helps locate small leaks

Which method is best depends on the pipe type, where it runs and the likely cause. A good plumber will often combine them.

When to call a plumber

Call a licensed plumber if your meter test shows water moving when everything is off, if you can see water damage or smell mould, or if your bill has jumped for no clear reason. Leaks rarely fix themselves and tend to get worse. Water can also damage floors, cabinetry and the structure of your home, and long-term dampness can lead to mould.

If water is flowing freely or flooding part of your home, turn off the water at the main isolation valve or at the meter and call for urgent help. If water is near electrical outlets or appliances, stay away and switch off power at the switchboard only if it is safe to reach.

It’s also worth knowing where your main water shut-off is before you ever need it. Show everyone in the household where it is.

Think you have a hidden leak? Call The Plumbing Gang on 1300 671 525 or see our water damage and leak services. You can also read more about our leak detection work.