Every leak article tells you to look for a wet patch. Here there will not be one

Search for how to find a water leak and you will get the same list everywhere: look for a damp patch, a soft spot in the lawn, an area of grass greener than the rest, water seeping from a path. It is good advice and it works in most of Sydney.

It does not work here, and the reason is the ground. On permeable sand, water from a leak drains vertically rather than pooling. There is no wet patch, no soft spot and no greener grass, even where a substantial amount of water is escaping every day. The ground takes the evidence away before anybody can see it.

The short answer

On free-draining ground the visual signs of a leak simply do not form, so the absence of a wet patch tells you nothing at all. The water meter is the test that still works: turn everything off, make sure nothing is refilling, read the meter, wait an hour and read it again. Any movement means water is leaving the system.

1. Stop looking for a wet patch. It is not going to appear
2. Do the meter test with everything off and nothing filling
3. Repeat it with the hot water system isolated to halve the search
4. Listen at the meter and in a quiet house at night
5. Watch the bill, because on this ground it is often the first sign

On this page

1. Why the signs never form
2. The meter test
3. The other signs
4. Finding where
5. Why it matters more here
6. A habit worth having

1. Why the usual signs never form here

A wet patch is not caused by water arriving. It is caused by water arriving faster than the ground can take it away. In heavier soil that happens easily, the water backs up to the surface, and you get the sign everybody is taught to look for.

Permeable sand takes water away roughly as fast as a domestic leak can deliver it. The water goes down, not sideways and not up. So the surface stays exactly as it was, the grass looks the same as the rest of the lawn, and there is nothing to find.

The uncomfortable consequence is that on this ground a leak can run for a very long time. Not because anybody was careless, but because the property was showing no signs and there was nothing to prompt anybody to look.

2. The test that still works

1. Turn off every tap in the house.
2. Make sure nothing is refilling: no cistern running, no ice maker, no irrigation timer about to start, no washing machine mid-cycle.
3. Go to the meter and read it, including the fine dial that shows small usage.
4. Use no water at all for an hour.
5. Read it again.
6. Any movement at all means water is leaving the system somewhere.

That is the whole test. It costs nothing, it takes an hour of not using water, and on this ground it is the only reliable evidence available. Worth doing a couple of times a year as a matter of habit rather than only when something seems wrong.

One refinement doubles its value: isolate the hot water system and repeat. If the meter stops moving, the loss is on the hot side. That single answer halves the search before anybody has been paid to look.

3. The signs that do still exist

• The bill. On this ground it is frequently the first indication, because nothing visible arrives to warn you. A bill that has drifted up with no change in the household is worth taking seriously.
• Sound. A quiet house at night is a surprisingly good instrument. So is putting an ear near the meter with everything off.
• Pressure that has fallen without an obvious cause.
• Ground that has moved rather than ground that is wet: a paver rocking, a path dropping, a dry depression. Covered properly in our guide on voids.
• A hot water system running more than it used to, where the loss is on the hot side.

Notice that all of those are indirect. That is the nature of the problem here, and it is why the meter matters so much: it is the one direct measurement available.

4. Knowing there is one, and finding where it is

The meter tells you there is a loss. It does not tell you where, and on ground that produces no surface clue there is nothing to narrow it down by eye.

So locating is done by isolating sections and testing them, then by acoustic and correlation equipment on the section that is losing. On a property where nothing surfaces, that equipment is not a luxury. It is the difference between a targeted repair and excavating on a guess.

It is worth pressing on this when comparing quotes: ask how the leak will be located, not just what a repair costs. A quote that assumes somebody will find it by looking is a quote written for different ground.

5. Why an unfound leak matters more on this ground

Beyond the water bill, there is a second cost that is specific to sand.

Water escaping under pressure moves fine material with it. Over months and years that redistributes ground away from where it was, and because this ground does not bridge over the resulting space the way heavier soil does, it eventually shows up at the surface as movement: a paver that rocks, a path that has dropped, a crack that keeps opening.

So a leak that leaves no trace for two years is not harmless during those two years. It is quietly doing something that will be visible later, in a form nobody connects back to plumbing.

6. The habit worth having on this ground

1. Do the meter test twice a year. Put it with something you already do seasonally.
2. Glance at the bill each time it arrives, for the trend rather than the number.
3. Fix a dripping tap or a running cistern promptly, because they mask a real loss in the same test.
4. Know where your main isolation valve is and check it turns.
5. If anything at the surface has moved, note where relative to the drainage.
6. Keep any leak detection report and its findings with the house papers.

None of that is onerous, and on ground that hides leaks completely it is the only monitoring available. It is also why we would rather tell people the test than sell them an inspection they do not yet need.

The short version

• Permeable ground drains a leak vertically, so no wet patch, soft spot or green grass forms.
• The absence of a visible sign is not evidence of no leak on this ground.
• The meter test still works: everything off, nothing filling, read, wait an hour, read again.
• Isolate the hot water system and repeat, and you have halved the search for free.
• The bill is frequently the first indication, because nothing visible arrives to warn you.
• An unfound leak also moves ground, which shows up later as surface movement.