By Matthew Baring-Gould, Kingscliff-based drainage plumber. Servicing Tweed Heads for 4 years. 5.0 stars across 173 Google reviews. Licensed NSW 383340C and QLD 15036450. ABN 74 605 392 348.
Water leak at a Casuarina property after the water meter. Called in a leak detection crew first, who located the leak under the pebbled area in the back garden at roughly 500-600mm depth. Exposed the 25mm poly line and removed the damaged section. The poly had been rubbing on a rock or the footings of an adjacent brick wall. Repaired with new 25mm poly and two joiners. Wrapped the repair with geofabric to protect the pipe from future rubbing. Backfilled and cleaned up.
What the customer called us for
Owner called us out for a water leak that was showing on their water bill and in the pebbled area of the back garden. Leak detection had not yet been called in.
What we found when we got there
We coordinated the leak detection mob to attend first because narrowing the leak to within a metre before digging saves hours of excavation. Leak was located under the pebbled area at 500-600mm depth. When we dug down, we found the 25mm poly water line had been rubbing on either a rock or the footings from the brick wall above it. Over years, the rubbing had worn through the pipe wall. Classic hidden-damage problem on underground poly runs.
Why we did it this way
Poly water pipe is tough but it is not indestructible. If any hard object (rock, broken concrete, brick footing) sits against the pipe and there is any ground movement over years, the hard object slowly wears through the pipe wall. The repair itself is straightforward: cut out the damaged section, join new poly in with joiners. The important detail is wrapping the repair in geofabric so the new pipe does not rub on the same rock in a few years. Without the lag, you fix the same leak again in 2027.
What we did on site
- Called in leak detection to locate the leak before excavating.
- Exposed the 25mm poly line at 500-600mm depth under the pebbled area.
- Identified the damaged section where the pipe had been rubbing on a rock or footing.
- Cut out the damaged section.
- Repaired with new 25mm poly line and two joiners.
- Lagged the repair with geofabric to protect against future rubbing.
- Backfilled the excavation and replaced the pebbles.
- Cleaned up the area on completion.
The result
Water leak fixed. Repair lagged with geofabric so the new section is physically protected from the rock that caused the original damage. Owner’s water bill should return to baseline.
If you have the same issue
If your water bill suddenly jumps or you can hear running water with everything turned off, you have a leak somewhere. Call leak detection first, then a plumber. Narrowing the leak location before digging saves hours. If the pipe is poly and the damage is in a rocky or compacted area, make sure the repair gets lagged with geofabric – otherwise you will be fixing the same spot again in a few years. Call Matty on 0447 188 394 or request a quote.
Customer names and addresses have been withheld. Individual results vary. Drain Masters Plumbing is licensed in NSW (383340C) and QLD (15036450).
Frequently asked
What is a leak detection mob and why not just dig?
A leak detection crew uses acoustic listening equipment and sometimes tracer gas to pinpoint the leak location to within a metre, without any digging. That saves you hours of excavation and surface reinstatement. For any underground water leak on a residential property, calling leak detection first is almost always cheaper than guess-and-dig.
Why does poly pipe fail if it is rubbing on a rock?
Poly is a semi-soft plastic designed to be flexible in ground movement. When any hard object sits against it with sustained pressure, the pipe wall deforms and eventually wears through. Over 10-20 years of ground movement, even a small rock in the wrong place will wear a hole. Lagging with geofabric creates a buffer zone that absorbs the micro-movement.
How long does the repaired section last?
The new 25mm poly is rated for 50+ years in normal ground conditions. With the geofabric lag protecting against the specific rock that caused the original problem, the repaired section should outlive the house. The rest of the water line is still the original age though, so other sections may develop their own issues over time.
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