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Sydney Water Smoke Testing: What It Means for Your Home

Smoke rising from your roof vent is normal. Smoke from the lawn, a drain grate or a downpipe can mean a fault in the pipes on your property. Here is what the test finds, what Sydney Water asks of owners, and how it gets fixed.

★★★★★4.9 1,249 Google ReviewsPosted by Mr Splash · 21/10/2026 · Reviewed by our licensed team (Lic #306457C)

The Short Answer

Smoke from your roof vent is fine. Smoke anywhere else is worth a look.

Sydney Water pushes a mist-like smoke into its sewer pipes to find where rainwater gets in. Where it escapes shows where there may be a crack or a wrong connection. Faults on your property are yours to fix, and Sydney Water requires a licensed plumber or drainer to do it.

1300 677 752Tap to Call - 24/7

Licensed & insured · Lic #306457C

White smoke rising from a garden bed beside a capped inspection opening at the edge of a lawn — Where smoke comes up out of the ground during a test shows where there may be damage, Sydney Water says.

What Is Smoke Testing?

When it rains, stormwater can get into Sydney Water’s sewer pipes. Sydney Water says that extra water can overload the system and push sewage out into local waterways and onto properties, even inside homes. Its Wastewater Fix program is finding where the rainwater gets in.

To find the leaks, a crew pumps a small amount of smoke into the pipes on your property. It goes in through the inspection opening (a capped pipe in your yard that gives access to the sewer) or a maintenance hole. Sydney Water says wherever the smoke comes out above the ground shows where there may be damage or a pipe connected to the wrong system.

Key Facts From Sydney Water

The smoke is “more like a mist”. It is environmentally safe and clears in a few minutes without any odour. Fact sheet
Smoke from the vent pipes on your roof is normal. It shows your pipes are connected correctly. Fact sheet
Sydney Water updates you about a week before it starts, and writes to you if it needs to come onto your property. Fact sheet · Wastewater Fix
The check takes about 30 minutes and covers the wastewater and stormwater pipes on your property. Wastewater Fix
Your water, taps and toilets keep working as normal during the test. Fact sheet
You own the wastewater pipes on your property and are responsible for them, and repairs must be done by a licensed plumber or drainer. Customer Contract

Where the Smoke Comes Out, and What It Means

Smoke takes the same path rainwater does. Here is what it means in each place you might see it.

Worth a Look

White smoke rising through the round grate of an overflow relief gully beside a brick wall — Smoke rising through a gully grate during a smoke test.

Check this

Drain Grate Outside the House

This round grate on the ground is called an overflow relief gully. Sydney Water says it should work like a safety valve for the sewer, so an overflow spills outside instead of inside your home. If it is damaged or sits too close to the ground, rainwater runs straight into the sewer.

White smoke drifting up out of a mulched garden bed beside an inspection opening and a metal fence — Smoke coming up through a garden bed during a smoke test.

Check this

Lawn or Garden Bed

Smoke coming up through the grass or soil points to a cracked, broken or unsealed pipe or joint under the ground. Sydney Water says finding these is one of the main things the test is for.

Check this

Downpipe

Rainwater from your roof should run into the stormwater system, not the sewer. Sydney Water checks that downpipes are not connected to the sewer, and its diagram shows smoke from a downpipe means it is.

White waste pipe and trap under a bathroom vanity — Photo: a Mr Splash job in Sutherland.

Check this

Inside the House

Sydney Water says smoke can sometimes come inside through kitchen, bathroom or laundry drains. The pipe under every sink bends and holds a little water, and that water stops the smoke. That is why it asks you to put some water in your sinks and cover your floor drains while it tests. If you see smoke inside, tell the crew. Sydney Water says it is not a fire and clears in a few minutes with normal ventilation.

Normal

Roof Vent Pipe

Smoke from the vent pipes on your roof or the side of your house is meant to happen. Sydney Water says it shows the vents work and your pipes are connected correctly. Nothing to fix.

After the Test

Sydney Water leaves a card in your letterbox when it has finished. Once its inspections are done, it tells owners about any repairs it found and the steps to take.

If Sydney Water Is Testing Your Area

Here is what Sydney Water asks of you, and what to expect on the day.

Look out for an update. Sydney Water says it updates you about a week before it starts, and writes to you if it needs to come onto your property.
You do not need to be home. Lock up pets, unlock gates, and make sure the crew can safely reach your front and back yards.
Put some water in every sink and cover the floor drains in your kitchen, bathroom and laundry.
Expect about 30 minutes on your property: a look around, then smoke through your wastewater and stormwater pipes.
The smoke machine runs off a generator that sounds like a lawn mower, in short bursts.
Rain, cloud or wet ground can push the test to another day.
Keep using your taps, toilets and showers as normal. Your water is not affected.

If Sydney Water Finds a Defect

Sydney Water says owners own and are responsible for the wastewater pipes on their property, up to and including the point where they connect to its system. If the test turns up a fault on your side, expect a letter asking you to fix it. Read it for the deadline that applies to you.

Two things are worth knowing. First, Sydney Water requires the repair to be done by a licensed plumber or drainer, so a handyman fix will not do. Second, its customer contract lets it restrict or disconnect your system until a defect is fixed, and fix the defect itself and charge you the reasonable cost.

Before you book anyone, check their licence on Verify Licence NSW. Ours is 306457C.

How a Licensed Plumber Fixes It

A defect letter tells you that smoke came out in the wrong place. It does not always tell you why. This is how we work it out and put it right.

Camera Inspection First

We run a CCTV drain camera through the line to find exactly where it is cracked, misconnected or root-damaged. The camera inspection is free with any booked drain service.

A Fixed Price Before Work Starts

You get an upfront, fixed price for the repair. You pay nothing until you accept it, and it does not move while we work.

The Right Repair for the Fault

Re-run a downpipe to the stormwater, raise or replace a damaged gully, dig out and replace a broken section, or reline a cracked pipe from the inside so most of the yard stays put.

Work That Is Guaranteed

Every job is done by our licensed team (Lic #306457C), fully insured, with a lifetime guarantee on workmanship.

A drain camera screen beside an open inspection point — Our camera checking a sewer line in Beverly Hills.

New white stormwater pipe laid in a trench beside a lawn — A cracked stormwater pipe we dug out and replaced in Jordan Springs.

Looking along the inside of a relined pipe — Inside a stormwater pipe we relined in Linley Point.

Smoke Testing Questions, Answered

Is the smoke from a Sydney Water smoke test safe?

Sydney Water says the smoke is more like a mist and is environmentally safe, and that it disappears after a few minutes without any odour. It is not a sign of fire, but let the inspection team know if you see smoke inside your home.

Why is smoke coming out of my roof vent?

That is what is meant to happen. Sydney Water says smoke from vent pipes shows they are working and your wastewater system is connected correctly.

How do I get ready for a smoke test?

Put some water in every sink and cover the floor drains in the kitchen, bathroom and laundry. Sydney Water may postpone the test if it is raining, cloudy or the ground is too wet.

Who pays to fix a fault on my property?

Sydney Water says owners own and are responsible for the wastewater pipes on their property, up to and including the connection point to its system. Repairs to those pipes are the owner’s cost.

Can a handyman fix a Sydney Water defect letter?

No. Sydney Water requires repairs to private wastewater pipes to be done by a licensed plumber or drainer. You can check any plumber’s licence on Verify Licence NSW before you book.

What happens if I ignore a letter from Sydney Water?

Read the letter for the deadline it gives you. Sydney Water’s Customer Contract lets it restrict or disconnect your system until the defect is fixed, and fix the defect itself and charge you the reasonable cost.

Got a Letter From Sydney Water?

Call us with the letter in hand. We will book the camera inspection, find the fault and give you a fixed price to fix it. 24/7 emergency service, Sydney wide.

1300 677 752Tap to Call - 24/7

Licensed & insured · Lic #306457C