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Find a hidden leak with your water meter

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Before anyone opens a wall or quotes for leak detection, your meter will tell you free whether you have a leak at all — and roughly whose it is.

A high bill, a damp patch, a warm spot on a slab floor, or a pump that starts when nothing is running: all of them point the same way, and all of them get answered by the same test.

Step 1: shut everything off

Turn off every tap inside and outside. Make sure the washing machine and dishwasher are not mid-cycle, the toilets have finished refilling, any irrigation controller is off, and — importantly — any evaporative cooler, ice maker or rainwater-to-mains switching device is not about to top itself up. These are the classic false positives.

Step 2: read the meter properly

Find the meter, usually near the front boundary. Note the full reading including the small digits, and look for a leak indicator: a small dial, star or triangle that spins on flows far too low to move the numbers. Many meters have one, and it is much more sensitive than watching the digits.

If the leak indicator is turning with everything off, you have a leak, and you already have your answer.

Step 3: wait, then read again

Leave it for at least twenty to thirty minutes with nothing running, then read again. Movement with everything off means water is going somewhere.

Overnight is even better if the reading has not moved but you still suspect something: take a reading last thing at night and first thing in the morning, with the household warned not to use water.

Step 4: work out which side it is on

This is the step people miss, and it is the one that decides who pays.

Find the stop tap — usually at the meter — and close it. Everything in the house should now be without water; confirm at a tap. With the stop tap closed, watch the meter again.

  • The meter stops → the leak is on your side: your service pipe, or somewhere in the house.
  • The meter keeps moving with the stop tap fully closed → water is passing between the meter and your stop tap, which is generally the water authority's side. Report it to them rather than paying for leak detection.

Narrowing it down inside the house

If it is your side, isolate progressively. Close the isolation valve to the hot water system and repeat: if the meter stops, the leak is on the hot side or at the system. Close isolation valves under toilets and basins one at a time.

The most common culprits, roughly in order:

  • A toilet trickling into the pan. Silent, continuous, and the single biggest domestic water waster. Put a few drops of food colouring in the cistern, wait, and look in the pan — colour appearing without flushing is a failed outlet valve seal.
  • A dripping tap, especially outside where nobody hears it. See dripping tap.
  • Irrigation: a stuck solenoid or a cracked poly line under mulch.
  • A flexible hose under a sink or basin.
  • A service pipe leak underground between meter and house — often visible as a permanently green patch of lawn, or a soft spot.
  • A slab leak, where the pipe runs in or under a concrete slab. The tell-tale is an unexplained warm area on the floor if it is the hot line, and it is the case where professional leak detection genuinely earns its money.

Two things this test does not tell you

It does not find where the leak is on your side, only that there is one — that is what acoustic and thermal leak detection is for. And it does not detect a leak that is not on the pressurised supply: a waste pipe leaking under a shower shows up as damage, not on the meter, because that water has already been counted.

Know where your stop tap is before you need it, and check that it turns. The most useful thing in a burst pipe is being able to shut the water off in under a minute. A stop tap that has not been turned in fifteen years is often seized — finding that out during an emergency is the wrong time. If yours will not move, that is a small job to have done on the next visit, not something to force.

What to do with the answer

Repairs to your service pipe, to concealed pipework, or anything requiring cutting into the supply are plumbing work in Australia — see licensed work. What you have gained from the test is the ability to walk into that conversation knowing there is a real leak, roughly where it is not, and whether it is even yours.

Frequently asked questions

How do I know if a leak is my responsibility or the water authority's?

Close the stop tap at the meter and watch the meter. If it stops, the leak is on your side. If it keeps moving with the stop tap closed, water is passing before your side and it is generally the authority's to fix — report it rather than paying for detection.

What is the small spinning dial on my water meter?

A leak indicator. It turns on flows far too small to move the digits, which makes it the most sensitive part of the meter for finding a slow leak.

How can I check if my toilet is leaking?

Put a few drops of food colouring in the cistern and wait without flushing. If colour appears in the pan, the outlet valve seal is passing — a silent leak that runs continuously.

Will the meter test find a leaking shower waste?

No. The meter only sees water on the pressurised supply. A waste or drainage leak has already passed the meter, so it shows up as damage rather than as consumption.

Sources

What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.

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