Underground water leaks are one of the most difficult plumbing issues for homeowners to spot early. These
hidden leaks can occur beneath soil, concrete, driveways or garden areas, and often go unnoticed until major damage has already begun. Early detection is the key to preventing structural issues, water wastage and high water bills.
Table of Contents
- What underground water leaks mean
- Early warning signs
- Common causes
- DIY ways to check
- What homeowners can do
- When to call a plumber
- Long-term prevention
- FAQs
- Bottom line
What underground water leaks mean
An underground water leak happens when a water supply pipe cracks, corrodes or splits below the surface. These pipes supply clean water to your home — meaning any leak will continue running 24/7 until repaired. Over time, this causes soil erosion, damage to concrete and higher water bills.
Early warning signs
Look for:
- damp, soft or sunken sections of lawn
- unusually green patches of grass
- mould growing on exterior walls
- water pooling in unusual areas
- a sudden increase in water bills
- the sound of water running when taps are off
- cracks in paths or driveways
- soil washing away around the house
These signs often mean water is escaping below ground.
Common causes
The most common causes include:
- corroded or ageing copper pipes
- poor installation or old fittings
- tree root pressure on water lines
- ground movement
- vehicle pressure on driveways
- previous repairs failing
- incorrect pipe sizing or materials
DIY ways to check
You can run a simple water meter test:
- Turn off all taps and appliances.
- Locate your water meter.
- Write down the reading.
- Wait 15 minutes.
- Check the meter again.
If the numbers move — and no water is running — you may have a leak.
Another test is to turn off the main valve inside the house.
If the meter still moves, the leak is between the water meter and your home.
What homeowners can do
You can:
- monitor your water bills
- perform regular water meter tests
- inspect the yard for changes in soil
- check for dampness around exterior walls
- keep large trees away from water lines
These steps help catch leaks early, but won’t fix the issue.
When to call a plumber
Call a plumber if:
- you confirm movement on the meter when water is off
- your yard or concrete is sinking
- you see pooling water with no clear source
- your water bills suddenly spike
- you suspect a burst or cracked pipe underground
- you hear water running inside walls or underground
Our emergency plumbing page is here:
https://www.smartchoiceplumbing.com.au/emergency-plumber-in-campbelltown/
Long-term prevention
Prevent future leaks by:
- replacing old copper or galvanised pipes
- avoiding tree planting over water lines
- upgrading to modern durable piping
- regularly checking your meter
- booking routine plumbing inspections
FAQs
Does an underground leak always cause a high water bill?
Usually yes — underground leaks constantly run, increasing your consumption.
Will tree roots damage water pipes?
Roots put pressure on pipes and can cause cracks or movement.
Can underground leaks damage a house foundation?
Yes, water can wash away soil and weaken slab support.
Underground leaks can cause major damage and waste thousands of litres of water. Early detection and quick action are essential. If you suspect a leak or your meter shows unexplained movement, Smart Choice Plumbing can locate and fix the problem before it becomes costly.
