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Smoke Testing in our Wastewater Network

We annually conduct a smoke-testing program within our wastewater network to identify and address issues related to Inflow & Infiltration. During this period, you may observe smoke emerging from drain grates, manhole lids, and downpipes.

Smoke testing involves introducing a dense, non-toxic, and odourless smoke into the drainage system to locate any points where the smoke escapes. It is common to see smoke from wastewater vent pipes on roofs, which is normal and does not indicate an issue. However, smoke emerging from storm drains, lawns, pavements, or streets could signal problems such as cracked wastewater pipes or damaged manholes, or cross-connections with the stormwater network.

The 'smoke' used in this testing is not true smoke but rather a harmless white vapour, similar to that used in smoke machines at events. It is safe for humans, animals, and plants, leaving no residue, stains, or smell. It poses no fire hazard and dissipates quickly.

If smoke enters your home, simply open windows at both ends to allow it to clear, typically within minutes. This occurrence may indicate plumbing issues within your home, prompting you to contact a licensed plumber for inspection and any necessary repairs.

The wastewater and stormwater networks are separate systems designed to handle specific types of water. If these systems cross-connect, it can lead to environmental harm, such as contamination of waterways, or system stress causing overflows during heavy rains. Smoke testing helps identify such cross-connections and other infrastructure defects, like pipe breaks or faulty manholes.

Here are some FAQs to clarify what smoke testing entails and its implications for our community:

Smoke testing involves injecting dense, non-toxic, and odourless smoke into sewer or stormwater systems through manholes. The smoke fills the pipes and escapes through any breaks, helping to pinpoint areas needing attention.

Our stormwater system is designed solely for rainwater runoff, while the wastewater system handles sewage. Identifying any improper connections (cross-connections helps prevent contamination of water bodies. Similarly, preventing stormwater from entering the wastewater system avoids overflows and protects our treatment processes.

Before each testing round, we notify affected residents via mailed letters and Council Facebook groups. We also inform the fire service of our operations.

No, the smoke is harmless vapor, safe for humans, animals, and plants. It disappears quickly and does not leave any lasting effects, though direct contact may cause minor respiratory irritation in sensitive individuals.

Do not be alarmed. Open windows for ventilation and note the smoke's source. If concerned, leave your home and inform nearby testing personnel. It's a precaution until we confirm the smoke's origin, which could indicate plumbing issues requiring a plumber's attention.

Ensure all drain traps (U-traps) contain water by running water into infrequently used drains before testing. This prevents smoke from entering your home through sinks and drains.

Yes, smoke alarms may trigger during testing. Open windows and doors to ventilate, as this is normal during smoke testing operations.

Council uses findings to plan future infrastructure improvements and prevent stormwater and surface water from entering the sewer system. Depending on the location of leaks, property owners may be responsible for implementing these fixes.

Common outcomes from smoke testing

1. Smoke or no smoke from Terminal Vent:

Indicates that no smoke was observed on the property unless explicitly stated or access was not possible to confirm visually. Additionally, there was no smoke seen exiting from the terminal vent where it should have been venting out.

2. Smoke from terminal vent - no smoke from storm water:

This indicates that smoke was observed coming from the terminal vent as expected, with no smoke detected from the storm water. This absence of smoke from storm water suggests no signs of a possible cross-connection.

3. Smoke coming out of the bushes:

Refers to smoke from testing emerging from the ground, specifically in an area with bushes. This observation may indicate a potential break or opening in the sewer line (whether private or council-owned), allowing smoke to rise and exit above ground, potentially leading to ground water entering the sewer network.

4. Smoke appearing to come out of the ground around the gully trap or adjacent area:

This describes smoke from testing exiting the ground near the gully trap or its surroundings. It suggests a possible break, crack, or opening in the line, enabling smoke to escape. The gully trap should prevent smoke from exiting by holding water to block sewer gas/smell.

5. Smoke emanating from a stormwater drain on the driveway at the rear of the property:

Indicates that smoke was observed exiting a stormwater asset on the property, potentially allowing storm water to enter the sewer network. Smoke should only be exiting from the terminal vent on the property.

6. Manhole on the front lawn emitting smoke from the edges/seal:

This notes that smoke is escaping from a manhole at its seal/edge. While manholes typically emit smoke from the keyhole, this observation suggests that the seal is not properly sealed, allowing smoke to exit.

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