Multiple Drains Blocked Caulfield East VIC 3145 – Boundary Trap and ORG Overflow from Full Sewer Blockage

Overview of the Problem – Multiple Drains Blocked or Overflowing

At a property on Moodie Street in Caulfield East VIC 3145, our team at Your Choice Plumbers was called out after the owners noticed sewer overflow first appearing near the front driveway and then on the side of the house where they normally hang washing.

This is exactly the type of situation where homeowners start asking, “why are multiple drains backing up at once?” or “why is sewer water overflowing outside the house?” As an experienced plumber Caulfield East, we often find that when several fixtures begin showing symptoms at the same time, the problem is no longer an isolated drain issue — it usually means the main sewer line is blocking up.

In this case, the earlier warning signs had already been present. The drains had started gurgling, but the signs were neglected until the system progressed to full surcharge and overflow.

Early Warning Signs That Pointed to a Main Sewer Blockage

When we spoke with the client, they explained that:

• the toilets were still flushing, but slowly
• sewer overflow was first noticed near the boundary trap area at the front driveway
• overflow then appeared at the side of the house through the overflow relief gullies serving two separate bathroom fixtures

These details were very important.

The combination of:

• gurgling drains
• slow toilet flushing
• overflow from the boundary trap multi-vent cap
• overflow from two separate overflow relief gullies

made it clear this was a full sewer line blockage, not a simple local drain problem.

Why the Fixtures Were Still Draining Even with a Full Blockage

Further investigation confirmed that the home was an older bungalow-style property on stumps, sitting around 500mm above natural ground level on a flat block.

That structural detail helped explain why the fixtures were still partly usable even though the sewer was fully blocked.

Because the house was elevated, there was still enough head pressure from the raised internal fixtures to push wastewater down through the drainage system temporarily. However, instead of discharging freely into the authority main, the wastewater was surcharging and overflowing at the lowest relief points:

• the boundary trap vent
• the overflow relief gullies (ORGs)

This is a very important concept for homeowners, because it explains why people sometimes think “the drains are still working” when in reality the sewer is already fully blocked and discharging outside.

Locating the Sewer Blockage at the Boundary Trap Connection

Based on the symptoms and testing, our diagnosis was that the blockage was located downstream of the boundary trap connection.

The boundary trap shaft was full and actively overflowing, which told us the sewer could not discharge properly into the South East Water main.

To restore flow, we used our high-pressure jet drain cleaning machine through the boundary trap connection. This successfully broke through the blockage and allowed the sewer to begin flowing away into the authority main again.

Identifying the Cause of the Full Sewer Backup

While the sewer was draining away, we focused on cleaning up the overflowed wastewater from the driveway and the side of the house.

During that process, we found excessive amounts of baby wipes in the sewer surcharge.

When we asked the owners about this, they explained they had hosted a party over the weekend. That likely explained how the wipes had entered the system. Guests unfamiliar with the property had probably flushed the wipes, not realising they do not break down like toilet paper.

This is a very common cause of multiple drains blocked events in residential homes.

Baby wipes tend to:

• stay intact in the sewer line
• catch on joints, rough sections, or sharp pipe edges
• build up quickly with paper and waste
• create a full choke point in the sewer system

Clearing the Sewer System Properly After the Blockage Broke

Once the main blockage had broken and the sewer had drained into the South East Water main, we continued flushing and testing the system properly.

We:

• flushed all toilets multiple times
• ran the basins, showers, and other fixtures
• made sure wastewater was discharging freely again

This step was important because once a full sewer blockage clears, there can still be waste residue left on the internal walls of the sewer pipe. If not washed down properly, that leftover material can quickly become the starting point for another blockage.

We also made sure the fixture traps were refilled with water. When the sewer suddenly starts rushing away after a blockage breaks, pressure changes in the pipework can siphon water from nearby traps, allowing bad sewer smell to enter the bathrooms.

Running the fixtures ensured the traps sealed again properly.

CCTV Inspection and Final Sewer Cleaning

After restoring flow, we inserted our Ridgid SeeSnake CCTV drain camera through the boundary trap shaft and inspected upstream along the main sewer run.

This allowed us to confirm whether any baby wipes were still stuck to the internal walls of the pipe.

To make sure the job was completed properly, we carried out additional high-pressure jetting to thoroughly wash down any remaining wipe residue or waste build-up inside the sewer line.

This final stage is critical in full sewer blockages caused by wipes, because partial clearing alone often leads to the same problem returning.

Sewer Overflow Clean-Up and Sanitising

Once the drainage system was confirmed clear, we completed the clean-up of the affected overflow areas.

This included:

• high-pressure washing of the driveway
• high-pressure washing of the side path
• treatment of the affected surfaces with chlorine solution

For sanitising, we used Clorox to help disinfect the sewer-affected areas after the overspill had been removed.

Outcome and Client Result

• full sewer blockage identified at boundary trap connection
• boundary trap and overflow relief gullies cleared of surcharge
• baby wipes confirmed as major blockage source
• sewer line restored to proper discharge
• fixtures re-tested and traps refilled
• CCTV inspection completed
• final washdown and sanitising carried out

The owners were relieved to have the sewer system flowing properly again and to understand what had caused the full overflow event.

Compliance & Prevention Insight

This case highlights why multiple drains blocked or overflowing should always be treated as a serious sewer issue.

When you start seeing:

• gurgling drains
• slow toilet flushing
• overflow from a boundary trap
• overflow from ORGs

the sewer system is already under pressure and may be close to full blockage.

It also reinforces an important homeowner lesson: baby wipes should never be flushed, even if packaging suggests otherwise. In real drainage systems, wipes are one of the most common causes of major residential sewer blockages.

Acting early when the drains first started gurgling could have prevented the full overflow around the house.

Compliance with Australian Standards

All work carried out by Your Choice Plumbers is completed in accordance with the relevant requirements of AS/NZS 3500.2:2021, helping ensure drainage systems are diagnosed, cleared, and restored correctly.

In simple terms, this means your sewer drainage is checked and cleared properly so wastewater can discharge safely, your fixture traps can reseal correctly, and the risk of repeat blockages is reduced.

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 blocked drains Melbourne services.