Stormwater and subsoil drainage in Traralgon

Water that pools in the yard, spills from downpipes or sits against the house after rain is a stormwater or subsoil drainage problem, and a licensed plumber or drainer fixes it by clearing, extending or relaying the pipes that carry roof and surface water away. In Traralgon the job often starts with a camera inspection, because a lost or collapsed stormwater line looks the same from above as a blocked one. Requests sent here go to an independent drainer or plumber who sets the price and carries out the job.

What counts as stormwater drainage?

Your property has two separate drain systems. The sewer drain takes waste from toilets, showers, sinks and the laundry. The stormwater system takes rain from the roof, gutters, downpipes, paved areas and yard pits, and carries it to the street drain or another legal point of discharge. Problems with toilets and sinks are sewer drain work, covered on the blocked drains page. This page is about the rain side.

Subsoil drainage is a third piece. It is perforated pipe laid in gravel below ground to collect water moving through the soil, usually beside a footing or at the bottom of a slope. It does a different job from a stormwater pipe and the two should not share a trench or a pipe.

Signs your stormwater system is failing

• gutters overflowing during rain even though they are clean
• a downpipe that bubbles or spills at the ground joint
• water ponding in the same spot every time it rains, where it never used to
• a wet patch at one corner of the house only, near a downpipe
• the ground or subfloor staying damp days after the rain has stopped
• soil washing out around a pit or along the line of a buried pipe
• a sinkhole or soft patch in the lawn over the drain

The timing tells a plumber a lot. Water that appears during rain is coming off a surface or a roof. Water that turns up a day or two later is moving through the ground, and that points to subsoil drainage rather than a stormwater pipe.

What are the usual fixes?

What you see	Likely cause	Usual fix
Downpipe spills at ground level	Blocked or collapsed pipe under the downpipe, roots, or a pipe too small	Clear the line, or camera it and replace the section
Pooling where it never used to	Stormwater line blocked, broken or lost	Camera survey, then clear or relay
Wet patch at one corner	Roof water discharged too close to the house	Extend the stormwater line away from the footing
Ground wet days after rain	Water moving through the soil	Subsoil drain to an outlet with fall
Water running across the yard from a slope	Overland flow from higher ground	Cut-off drain or swale above the building
Pit overflowing in heavy rain	Pit or outlet too small, or silted up	Clean out, or upsize the pit and outlet

This table follows the way The Quote Yard’s Gippsland plumbing price guide separates roof water, overland flow and water moving through the soil, which each need a different answer.

Why does heavy rain flood streets in parts of Traralgon?

The VICSES and Latrobe City Traralgon Local Flood Guide separates two kinds of flooding. Traralgon Creek has caused significant flooding in parts of town, and the guide notes that heavy rain falling within the town can add flash flooding from stormwater, which may arrive with little or no warning. It names the eastern side of town near the Princes Highway and Liddiard Road as particularly prone to flash flooding.

A plumber cannot stop a creek flood or the street drains backing up in a storm, and no drainage work makes a house flood proof. What good drainage on your block does is move roof and yard water away from the building quickly, keep downpipes from spilling against footings, and stop water ponding where it can get under the floor. The Traralgon area page has more on the town’s flood history, and the winter plumbing checklist covers the gutters and pits worth checking before the wet months.

Who looks after which drain?

Gippsland Water’s who does what page puts a stormwater drain or blockage with the local council, and says councils manage stormwater in urban areas. In practice the pipes on your property are yours to maintain, and the street drain, kerb outlet and council pits are the council’s. If the street drain is blocked and your line is clear, a plumber’s report or camera footage helps when you raise it with council.

Keep the two systems apart. Gippsland Water’s overflow relief gully page explains that the gully on your sewer drain must sit at least 75 mm above the ground so that stormwater cannot flow into it. Garden beds, paving or new soil that bring the ground level up around that gully let rain into the sewer. Roof water belongs in the stormwater pipes, never the sewer drain.

What does a careful drainer check?

Before quoting a stormwater job a good plumber or drainer will usually:

• watch where the water goes, ideally during or just after rain
• find the existing pits, downpipe connections and where the line leaves the property
• run a drain camera down a line they cannot see, and give you the footage
• check the fall available across the block, because water needs a slope to drain by gravity
• confirm the legal point of discharge, such as the kerb outlet or a council easement drain
• look at whether a new tank overflow or extension has been added to an old line that was never sized for it

A careful drainer will decline to run a new subsoil drain that has nowhere to discharge, because a drain with no outlet just holds water against the footing. On a flat block with no fall, the honest answer may be a sump with a pump and an alarm, and they should say so.

How is a stormwater line repaired or relaid?

1. Locate the line and pits, and camera the pipe to find the fault.
2. Clear the blockage with a drain machine or water jetter if the pipe is sound.
3. If the pipe is broken or full of roots, expose the damaged section.
4. Replace or relay the pipe with the correct fall, and add a pit or inspection opening where needed.
5. Reconnect downpipes and any tank overflow.
6. Backfill, reinstate the surface and test the line with water.

Where the job is above the set value, the plumber issues a compliance certificate. The design and installation of roof, surface and subsoil drainage to the point of connection are covered by AS/NZS 3500.3:2025, the stormwater part of the national standard, according to the Building and Plumbing Commission’s page on the AS/NZS 3500 series.

How much does stormwater work cost?

The Quote Yard’s Gippsland tables give a band of $170 to $390 per metre for stormwater drain laid, with depth, the surface being dug through and the fall available as the main variables. A camera inspection with footage and a report is listed at $290 to $560, and it is often the cheapest way to avoid digging in the wrong place. Breaking out concrete or paving and putting it back adds to the price. Other price bands are compared in the Traralgon plumbing cost guide. If you would like the drain surveyed before anything is dug, say so when you ask for a drainage quote.

Does a rainwater tank change the drainage?

A tank catches some roof water, but its overflow still has to go somewhere, and in a long wet spell a full tank sends nearly all of it on. That overflow is stormwater and should be piped to the stormwater system. The tank-to-house side of the job is on the rainwater tanks page.

Next step

Tell the plumber where water pools or sits, which downpipes spill, and whether the problem shows during rain or days afterwards. Describe the slope of the block and the location of any pits you know about. Photos or a short video taken during or after rain are the most useful thing you can attach. Then send a stormwater drainage enquiry with your suburb.

Send a job enquiry