Overview of the Toilet Leak Issue
At a property on Wembley Grove in McKinnon VIC 3204, our team at Your Choice Plumbers was called out after the owners noticed water leaking onto the floor around their toilet whenever it was flushed.
The toilet was a Caroma Luna Back To Wall Toilet Suite, which immediately made the diagnosis more challenging. This is exactly the kind of situation where homeowners start asking, “why is my toilet leaking on the floor when I flush?” or “how do you find a leak on a back to wall toilet?” As an experienced plumber McKinnon, we often find that back-to-wall toilet suites can hide the true source of a leak because the connection points are concealed and the pan is usually fully siliconed to the floor.
That means water can travel underneath the toilet and only appear at the edge of the silicone or through nearby grout lines, making the leak source difficult to confirm from the outside.
Initial Testing and Key Clues
During testing, we observed that each time the toilet was flushed, wastewater slowly trickled past the silicone line and onto the bathroom floor through the grout joints.
That was a very important clue.
Because the leak only appeared during flushing, it indicated the problem was most likely related to one of the waste discharge connections rather than a constant supply leak.
At that stage, the most likely fault points were:
- the flush pipe rubber
- the toilet outlet rubber
- the toilet connector assembly
Why Back-to-Wall Toilet Leaks Need Proper Access
We explained to the owners that with a back-to-wall toilet suite, the only proper way to diagnose the fault was to remove the toilet and inspect underneath it.
With these toilet designs:
- the pan connection points are concealed
- silicone around the base can hide water movement
- external inspection alone is often not enough
To diagnose the leak properly, we needed to disconnect the toilet, inspect the underside of the bowl, and check the condition of the connector and sealing rubbers.
The owners agreed to proceed.
Toilet Removal and Diagnosis
We carefully:
- cut out the silicone around the toilet base
- removed the fixing screws
- disconnected the flexible hose from the external mini stop
- pulled the toilet suite away from the wall for full inspection
Once the toilet was removed, we inspected the underside of the bowl and the concealed connection points.
There were no fresh stain marks where the bowl connects to the cistern, which allowed us to rule out a leak from the flush pipe rubber.
We then inspected the toilet connector seal and the real problem became obvious.
The connector rubber had perished over time and was no longer sealing correctly. Each time the toilet was flushed, wastewater was escaping around that failed seal and building up beneath the toilet. From there, it was tracking outward and eventually appearing through small gaps near the grout lines where the silicone seal was not fully watertight.
Repair and Toilet Reinstallation
Because the rubber seal on its own was not available separately — which is often the case with back-to-wall toilet suites — we advised the owners that the correct repair was to replace the entire toilet connector.
We sourced a new:
Caroma Uni-Orbital Connector – Long
from Reece Plumbing Caulfield.
We then:
- installed the new connector
- reinstalled the toilet suite back against the wall
- reconnected the flexible hose
- secured the toilet properly
- cleaned the area thoroughly
- tested the toilet for leaks and correct operation
The toilet flushed correctly and no further leak was present.
Outcome and Client Result
- floor leak accurately diagnosed
- failed connector seal identified
- complete toilet connector replaced
- toilet reinstalled and tested
- no further leak around the bowl when flushed
The owners were relieved to finally have the issue diagnosed properly, especially because the leak had been difficult to trace from the outside due to the concealed design of the suite.
Compliance & Prevention Insight
This case highlights why toilet leaks around the floor should never be dismissed as “just a bit of water.”
With back-to-wall toilet suites in particular, concealed connections and silicone around the base can make leaks much harder to trace accurately. Water often appears somewhere different from where the fault actually is.
It also shows why proper disconnection and inspection is sometimes the only reliable way to confirm the fault. Without removing the toilet, the failed connector seal could easily have been misdiagnosed.
Compliance with Australian Standards
All work carried out by Your Choice Plumbers is completed in accordance with the relevant plumbing standards, helping ensure leaking toilet repairs are performed safely, correctly, and with long-term reliability in mind.
In simple terms, this means your toilet is repaired properly so it can flush without leaking, protect your flooring, and avoid repeat issues.
Our Home Plumbing Experts Approach
As part of our Home Plumbing Experts approach, we focus on both repair and prevention.
We offer a Complimentary Property Protection Audit as part of our service, assessing key areas like water pressure, hot water temperature, and flexible hoses — helping homeowners stay ahead of potential plumbing failures and avoid unexpected water damage.
👉 Find out more about our leaking toilet repairs Melbourne services.
