Overview of the Problem – Stormwater Outlet or Legal Point of Discharge Has Failed
At a property on Bellevue Court in Mulgrave VIC 3170, our team at Your Choice Plumbers was called out after the owners reported overflowing downpipes and soggy grass in the front garden.
This is exactly the kind of issue where homeowners start asking, “why are my downpipes overflowing when the gutters are clear?” or “why is the grass always soggy at the front of the house after rain?” As an experienced plumber Mulgrave, we often find that when these signs show up together, the problem is often deeper in the stormwater system — especially at the legal point of discharge or main outlet line.
In this case, the investigation quickly pointed toward a failed stormwater discharge path rather than just a minor blockage.
Initial Investigation of the Legal Point of Discharge
In Mulgrave, many homes discharge stormwater to the curb and channel, so that was the first thing we checked.
The legal point of discharge at the street was found to be full of soil, which was already a strong sign that the system had not been discharging properly for some time.
We then inspected the downpipe connections to the underground stormwater drains and confirmed the below-ground system was still the original earthenware / terracotta pipework.
Another important clue was the pipe alignment. At the front of the property, it was clear the main stormwater line ran close to the left-hand boundary, directly beneath a row of pine trees planted along the fence line.
At that point, the likely causes were becoming clear:
- ageing original terracotta stormwater pipe
- blocked or failed curb outlet
- possible root intrusion from the tree line
Testing Whether the Main Stormwater Drain Was Still Intact
Before recommending repairs, we needed to establish whether the main stormwater line from the house to the legal point of discharge was still functional.
We proceeded with hydro jet drain cleaning Melbourne from the curb outlet back toward the property.
After approximately 1.5 metres of jetting, the water from the jetter began surfacing through the ground in the nature strip.
That immediately confirmed one major issue:
👉 the stormwater drain pipe had broken underground near the front outlet area
We continued clearing deposits and pushing further into the line until we reached another point where the equipment could no longer advance.
CCTV Inspection Confirmed Tree Root Damage
To investigate the second restriction properly, we used CCTV drain inspection Melbourne equipment and inspected the affected section by camera.
The drain camera clearly showed thick, chunky tree roots filling the line.
We then used the locator to pinpoint the exact location of the defect, which was approximately 300mm from the pine tree row.
At this stage, the two major defects were now confirmed:
- broken stormwater pipe in the nature strip near the curb outlet
- major root intrusion further back inside the front yard
With both defects present in the same front section of old terracotta stormwater drain, the best solution was no longer a patch repair.
Why Full Front Stormwater Renewal Was the Best Option
We explained to the owners that because:
- the drain was original
- multiple defects had already been confirmed
- tree roots had entered the line
- the legal point of discharge had failed
- and the system was already causing overflow and soggy ground
the smartest long-term solution was to replace the whole front section rather than keep repairing isolated failures.
The owners agreed, especially because they were concerned about potential future structural issues. That concern was valid. From our experience, failed stormwater drainage can contribute to:
- persistent water saturation around the home
- movement in the ground
- footing issues
- brick cracking and other structural stress over time
Smarter Stormwater Upgrade Without Cutting Concrete
The owners then asked an important question:
Could the rest of the stormwater system, including the house downpipes, also be renewed without cutting the concrete paths and driveway?
Because the house was on stumps and had usable space in the subfloor area, we confirmed there was a much smarter solution.
Instead of excavating around all the external paths and hard surfaces, we could:
- install new suspended stormwater drains under the house
- connect all house downpipes into the new suspended system
- then connect that new under-house line into the renewed external main stormwater drain
That meant the entire stormwater system could be upgraded properly without disturbing the concrete around the house or the driveway.
This turned out to be the ideal long-term solution.
Council Approvals and Stormwater Renewal Works
Before carrying out the renewal, we completed the required legal and service checks.
We:
- applied through City of Monash for legal point of discharge renewal approval
- lodged a Dial Before You Dig request for infrastructure checks in the work zone
- confirmed the external excavation area in the nature strip
Once all approvals were in place, we carried out the stormwater renewal works.
This included:
- excavating the original 100mm terracotta drain from the curb outlet back to the tree line
- installing new 100mm UPVC stormwater pipe and fittings
- renewing the front discharge section back to the house
- installing new 100mm UPVC suspended stormwater drains under the house
- connecting all downpipes into the new under-house drain system
- connecting the new subfloor stormwater line into the external main drain
We also used 100mm UPVC under the house instead of thinner 90mm pipe, because the thicker pipe offers better durability and protection even in subfloor areas.
New Access Point and Approved Kerb Connection
At the corner of the house where the main external stormwater drain connected into the new subfloor system, we installed:
- a 100mm UPVC junction
- a surface-level inspection opening with screw cap
This gives the owners a proper maintenance access point for the future.
At the street end, we also installed the Holman Kerb Adaptor, which is the approved adapter for connection into the council curb outlet in that area.
Outcome and Client Result
- failed legal point of discharge confirmed
- broken stormwater pipe located in the nature strip
- root intrusion confirmed inside the front yard
- front stormwater drain fully renewed
- new suspended under-house stormwater system installed
- downpipes reconnected without cutting concrete paths or driveway
- new inspection opening installed for future maintenance
- approved curb adaptor installed
The owners made a very smart decision to renew the whole system at once, giving them a new stormwater system without unnecessary disruption to the hard surfaces around the property.
Compliance & Prevention Insight
This case highlights why overflowing downpipes and soggy grass in the front yard should never be dismissed as minor stormwater problems.
When the legal point of discharge has failed, the whole drainage system can begin backing up. If the original pipework is also damaged, blocked by roots, or collapsing, the problem will only keep returning until the failed sections are renewed properly.
It also shows how important experience is in stormwater planning. In this case, a full system upgrade was possible without cutting concrete, because the house structure allowed a smarter suspended drainage solution under the home.
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 stormwater drainage systems are renewed, connected, and maintained correctly.
In simple terms, this means your stormwater system is built to discharge rainwater properly, protect the home from water build-up, and provide reliable long-term performance.
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.