About

Help us protect Tasmanian waterways and parklands

We live in one of the most beautiful parts of the world and our environment is particularly close to our hearts. Tasmania is home to some of the most stunning waterways and parklands and it is important that we all do our bit to protect the environment.

Stormwater inflow and infiltration

Our sewerage network is not designed to manage the inflow and infiltration of stormwater during rainfall.

Inflow is where stormwater enters the sewerage network, generally via private plumbing that is incorrectly connected to the sewer.

Infiltration is stormwater entering the sewerage network, generally by seeping through cracked, or unsealed underground infrastructure.

Below is a diagram that shows a correctly plumbed and incorrectly plumbed property.

Stormwater out of sewer

The effect of inflow and infiltration

When the amount of stormwater entering the sewerage network exceeds the network's capacity, there is potential for the following:

  • overflows to creeks, rivers and parklands
  • increased risks to the health of our waterways and local environment
  • increased sewage pumping and treatment.

FAQs

Frequently asked questions

We are inspecting sewerage infrastructure in areas where sewage overflows occur regularly, impacting the local environment.

Our crews will also work to identify and rectify any leaks and cracks in TasWater infrastructure.

We will notify property owners of any defects identified in their privately owned infrastructure and provide further information on your responsibility to rectify the issue.

Vapour testing helps us assess where stormwater may be entering our sewerage systems. We map out the drainage connections of an area, test, and then monitor for the release of any vapour during a test.

The testing involves injecting an odourless, non-toxic vapour (looks like fog) into the stormwater and/or sewerage system and monitoring the points of release.

Vapour testing of our sewer network may lead to you seeing mist or fog rise from maintenance holes, sewer vents and grates in the area.

If vapour is released from internal plumbing fixtures like your toilet or sink, open the building doors or windows to air out, and advise TasWater on 13 6992 or the contractors if they are nearby, as soon as possible.

Dye testing is an important tool in ensuring that stormwater and sewerage systems are functioning correctly. It is a simple and effective method that helps to protect the environment and public health.

During the test a small amount of florescent dye and water will be poured into downpipes and a sewer maintenance hole will be monitored downstream. If the dye appears in the sewer maintenance hole, this indicates that there is an incorrect connection between the stormwater and sewer systems. This can lead to issues such as sewage overflows during heavy rain and contamination of waterways.

The dye is odourless and non-toxic. Dye testing is used frequently in Australia and does not pose and risks to the environment or local community.


Tracker Monitoring is a service provided by contractors, Detection Services. We have engaged the contractors to install iTrackers within our sewer network to identify where we have inflow and infiltration issues.

The monitoring consists of a series of ultrasonic level sensors installed in sewer maintenance holes. These record the level of wastewater in the sewerage system and software converts this to flows. This helps to identify areas of the network that have higher than expected flows, particularly after rain events, which are related to stormwater entering the network.

This flow monitoring is an important step in helping us identify problems with our assets (leaky pipes or manholes) plus possible incorrect connections of private properties to the sewer system.

We all have a responsibility to minimise sewer overflows by being aware of and fixing incorrect connections on our properties. we will be checking your downpipe is connected to the stormwater system, not the sewer network.

If an incorrect connection is identified you should:

  • Contact your local council for advice on connecting to the stormwater system.
  • Contact a licensed plumber to fix any stormwater cross-connections or sewer defects.
  • Ensure your properties Overflow Relief Gully (ORG) is raised above ground level. Contact a licenced plumber before raising an ORG, if it is raised too high it can cause problems to your property.

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Nigel

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Resources

Examples of private property faults

Fault - Stormwater downpipe enters house's sewer system
Fault - Sump pump directly connected to the sewer via the overflow relief gully
Fault - Stormwater downpipe connected to the sewer
Fault - Tank overflow going into the overflow relief gully
Fault - Overflow relief gully not at regulation height
Fault - Overflow relief not at regulation height due to paving or concrete