Quick Answer
The clearest sign of an underground water leak is a water meter that keeps moving even when every tap and appliance in the house is switched off. Alongside this, look for a rising water bill with no change in usage, a soggy or unusually green patch of lawn, dropped water pressure, or the sound of running water with nothing turned on.
If any of that sounds familiar, here’s how to confirm it and what to do next.
Signs of a Water Leak Underground
Underground leaks are harder to spot than a dripping tap, because the evidence often shows up somewhere else entirely. Here’s what to look for:
- A rising water bill with no change in usage — This is usually the first and most reliable sign. If your routine hasn’t changed but your bill has, an underground leak is one of the most common explanations.
- A wet or soggy patch of lawn — Especially one that stays damp during dry weather, or that never seems to fully dry out.
- An unusually green or lush patch of grass — A leaking pipe effectively irrigates that one section of your yard, making it noticeably greener than the rest.
- Pooling water with no obvious cause — Puddles on the lawn, driveway, or path that appear without rain and don’t drain away.
- Dropped water pressure — If pressure at the taps or shower has weakened gradually, water may be escaping before it reaches your home.
- The sound of running water — A faint hissing, trickling, or gurgling sound coming from the ground or near your water meter, with nothing switched on.
- Cracking or sinking pavement — Escaping water can wash away the soil beneath a driveway, path, or slab, causing cracks or shallow depressions.
- A musty or sewage-like smell in the yard — More common with a sewer or stormwater leak than a fresh water line, but still worth investigating.
- Mineral staining or algae — Green or white staining on concrete or brickwork near ground level can indicate long-term water seepage.
One sign on its own isn’t always conclusive; a soggy patch could just be poor drainage. A few of these signs together are a much stronger indicator.
What Causes an Underground Water Leak?
Underground pipes usually fail for one of a few reasons:
- Ageing pipework — Many Brisbane properties still run on original pipework several decades old, which becomes more prone to corrosion, pinhole leaks, and joint failure over time.
- Tree root intrusion — Brisbane’s leafier suburbs are no stranger to this. Fig trees, jacarandas, and camphor laurels are particularly aggressive, with roots seeking out pipe joints in search of moisture.
- Ground movement — Reactive clay soils found across parts of Brisbane can shift slightly with seasonal wet and dry cycles, placing ongoing stress on buried pipe joints.
- Physical damage — Landscaping work, fence posts, or even heavy vehicles parked in the wrong spot can crack a pipe that’s sitting closer to the surface than expected.
Who’s Responsible: Before or After the Water Meter?
This is one of the most common questions we get, and it genuinely matters for your wallet.
According to Urban Utilities, the pipe between the water network and your meter is owned and maintained by Urban Utilities. Everything from the meter onward – including the underground pipe running from your meter to your home – is the property owner’s responsibility to repair and maintain.
In practical terms: if your water meter is ticking over and you’ve confirmed the leak, it’s almost always on your side of the meter, meaning it’s on you to get it fixed. Urban Utilities does offer financial assistance for concealed leaks in some circumstances, but the repair itself falls to a licensed plumber.
Two Simple Checks You Can Do Yourself
Before booking anyone, these two checks can help confirm whether you’re actually dealing with a leak.
1. The Water Meter Test
- Turn off every tap, appliance, and irrigation system in the house
- Locate your water meter (usually near the front boundary of the property)
- Take a reading, then wait 1–2 hours without using any water
- Check the meter again
If the reading has moved despite nothing being used, water is escaping somewhere in your system.
2. A Visual Walk of the Yard
Walk the length of where you know or suspect pipework runs, typically between the meter and the house. Look for the signs above: soft ground, unusually green grass, pooling water, or cracking pavement. This won’t confirm an exact location, but it can help narrow things down before a plumber arrives.
How We Detect an Underground Leak (Without Digging Up Your Yard)
Confirming there’s a leak is one thing; finding its exact location underground is another. Digging blindly to search for a buried pipe is expensive and unnecessary. Our team uses targeted detection methods to pinpoint the leak first:
Acoustic listening equipment
Water escaping a pressurised pipe creates a distinct sound that travels through soil and pipework. Acoustic listening devices help us track that sound to its source with real precision.
CCTV drain cameras
For leaks connected to underground drainage or sewer lines, a camera fed directly into the pipe lets us see cracks, joint separation, or root intrusion from the inside.
Isolation and pressure testing
By isolating sections of the water line and monitoring pressure, we can narrow down which section of pipe the leak is in before any digging begins.
Once the leak is pinpointed, repairs are targeted to that specific section, rather than trenching the entire yard to find the problem.
Why You Shouldn’t Wait
An underground leak doesn’t fix itself, and it rarely stays small for long.
- It keeps costing you — Every day it runs unfixed is more water (and money) disappearing into the ground.
- It can undermine structures — Sustained water loss can erode soil beneath driveways, paths, and even footings, leading to cracking and settling.
- It can affect your whole household’s water pressure — The more water is lost before it reaches your taps, the weaker your pressure becomes.
- Small leaks become bigger leaks — A pinhole leak under pressure typically gets worse, not better, over time.
Frequently Asked Questions
How can I tell if I have a water leak underground?
The most reliable way is a water meter test: turn off every tap and appliance, then check whether the meter is still moving. Combine this with visual signs like a soggy or unusually green patch of lawn, dropped water pressure, or an unexplained rise in your water bill.
What does an underground water leak sound like?
Often a faint hissing, trickling, or gurgling sound, particularly noticeable near the water meter or along the path of buried pipework, when no taps or appliances are running.
Who is responsible for fixing an underground leak in Brisbane?
Under Urban Utilities’ policy, everything from the water meter onward, including the underground line running to your home, is the property owner’s responsibility. Leaks on Urban Utilities’ side of the meter are their responsibility to repair.
Can an underground leak affect my water pressure?
Yes. If water is escaping before it reaches your home, less water is available at the tap, which often shows up as a gradual, unexplained drop in pressure.
How much does it cost to fix an underground water leak?
Costs vary depending on the leak’s location and severity. A CCTV drain inspection to confirm the issue typically runs $300–$500, while repair costs depend on what’s found. Our team provides a clear quote once the leak is located.
Can I just watch a wet patch and see if it goes away?
We wouldn’t recommend it. Underground leaks under pressure tend to get worse over time rather than resolve on their own, and the longer they run, the more they typically cost to fix, both in water usage and any resulting ground or structural damage.
Think You Might Have an Underground Leak?
If your water meter won’t stop moving or you’ve spotted a suspicious patch in the yard, don’t wait for it to get worse. Our team can pinpoint the exact location using targeted detection equipment, without unnecessary digging.
Contact our team or call 07 3254 8221 to book a leak detection inspection.