The clearest signs of a water main leak are an unexplained jump in the water bill, the sound of running water with every tap off, a constantly spinning water meter, damp or unusually green patches in the yard, low water pressure, and water pooling near the meter. A simple overnight meter test confirms it.
Key takeaways
- A sudden, unexplained rise in the water bill is the most common first sign of a main leak.
- The meter test confirms a leak: note the reading, use no water for 2 hours, and check if it moved.
- An always-damp or unusually green patch in a dry yard often marks the leak's location.
- The water main is buried and pressurised, so locating and repairing the leak is licensed plumbing work.
The 7 signs of a water main leak
A water main leak is the supply pipe between the water meter and the house leaking underground. Because it is buried, you rarely see the water itself, so you have to read the indirect signs. Here are the 7 that matter most.
- An unexplained spike in the water bill. A jump with no change in how the household uses water is the classic first sign.
- The sound of running water when every tap is off. A faint hiss or trickle near a wall or under the floor often points to a leaking supply line.
- A water meter that keeps moving with everything turned off. The meter should be still when no water is being used.
- Damp, soggy, or unusually green patches in the yard. A leak feeds that patch with water, so it stays lush while the rest of the lawn dries off.
- A drop in water pressure across the house. Water escaping underground means less reaches the taps.
- Water pooling or bubbling up near the meter or along the line between the meter and the house.
- Dirty or discoloured water at the tap, which can happen when soil is drawn into a cracked pipe.
How to confirm a leak with the meter test
Before calling anyone, run the meter test to confirm water is genuinely escaping. It is simple and it gives a plumber a clear starting point.
- Turn off every tap and water-using appliance inside and outside, including the dishwasher, washing machine, and any irrigation.
- Go to the water meter near your front boundary and write down the exact reading, including the small dials.
- Leave all water off for at least 2 hours, so do this when nobody needs water, for example overnight.
- Read the meter again. If the numbers have moved with no water used, water is leaking somewhere on your side of the meter.
- To narrow it down, turn off the tap at the house and repeat. If the meter still moves, the leak is in the main between the meter and the house.
Why Adelaide homes are prone to main leaks
A few local factors make water main leaks more common in Adelaide than people expect. Many established suburbs still have galvanised steel or early-generation supply pipe that has corroded over decades and is reaching the end of its life.
Adelaide's reactive clay soils are the bigger issue. They swell when wet and shrink when dry, and that constant ground movement through the seasons stresses buried pipes and pulls joints apart. The same soil movement that cracks driveways and paths also cracks water mains, which is why a long dry spell followed by rain is a frequent trigger for a leak to appear.
When to call a licensed plumber
A water main leak is not a DIY repair. The pipe is buried and under constant pressure, and the work sits squarely in licensed plumbing territory. Call a licensed Adelaide plumber if any of the following is true.
- The meter test confirms the meter is moving with all water off.
- Your water bill has jumped with no clear explanation.
- You have a persistently wet or green patch in an otherwise dry yard.
- Water is pooling or bubbling near the meter or along the supply line.
- Water pressure across the house has dropped noticeably.
What a leak detection plumber does
A licensed plumber locates a buried leak without digging up the whole yard. Acoustic listening equipment picks up the sound of water escaping under pressure, and tracer gas or pressure testing pinpoints the exact spot, so any excavation is limited to a small area.
Repairing or replacing the main is licensed plumbing work. Where the leak is on the property side of the meter it is the homeowner's responsibility, while a leak on the street side is SA Water's. A plumber will tell you which side the leak is on and handle any SA Water coordination needed. Acting early matters: a small main leak only gets worse, the bill keeps climbing, and saturated clay soil near footings can become a structural problem. Verify any plumber's licence free on the CBS public register before the work starts.