Wastewater testing

Why are you testing wastewater?

Wastewater monitoring can give a snapshot of the possible presence of SARS-CoV-2 - the virus that causes COVID-19 - in a local area.

We use this information alongside testing results and other health data in our response efforts.

Victoria has joined other Australian states and territories and New Zealand in collaborative research. This will help us to understand the occurrence of COVID-19 viral fragments in wastewater systems and use testing results with other health data in our response efforts.

Coordinated by Water Research Australia, the ColoSSoS (Collaboration on Sewage Surveillance of SARS-COV-2) project brings together health departments, water utilities, laboratories and researchers to share advances in this rapidly evolving field.

Wastewater testing is not new. This method has been used around the world to monitor poliovirus, norovirus and adenovirus in wastewater.

How do traces of COVID-19 get into wastewater?

People who have had COVID-19 may shed the virus or virus fragments on used tissues, off their hands and skin when washing, and in their stool.

Over time the virus breaks down and small pieces of the virus (called ‘viral fragments’) can enter wastewater through toilets, bowls, sinks and drains, and then travel through the sewer network.

While viral fragments may indicate that people within a community have or have recently had COVID-19, people can still shed the virus for several weeks, well beyond their infectious period.

How are wastewater samples taken and tested?

Samples of wastewater are collected every week from wastewater treatment plants and in the network at several metropolitan and regional locations.

The samples are analysed for viral fragments.

These tests detect the specific virus associated with COVID-19 and distinguish it from other types of coronavirus.

Where is wastewater being tested?

Since late August 2020, wastewater samples have been collected and tested from locations across the metropolitan and regional sewer network.

Wastewater samples are taken from about 140 sites including the large Melbourne Eastern and Western wastewater treatment plants, regional wastewater treatment plants and locations throughout the metropolitan sewerage system. 

Wastewater testing results

Click on each wastewater site below for historical testing results.

When more than 14 days has elapsed since the last detection and no new cases have been diagnosed, it is unlikely that there has been a local undiagnosed infectious person or community transmission.

Recurrent very low-level detections can be the result of a person or persons continuing to shed the virus.

Wastewater monitoring is increased at sites when viral fragments are detected in the absence of known cases.

Legend:

COVID-19 status within past seven days (From 5/3/2021)

Status	Icon
Unexpected detection
Anticipated detection
No detection
Test result pending
Inconclusive
No tests performed in this period
Testing site suspended

Latest status by testing site

Updated: 5/3/2021

Information about this data

Data presented in this interactive report is updated weekly. It is the most accurate data available to the Department of Health and Human Services at the time of publication. 

It can take two or more days from when a sample is taken to receive initial laboratory test results and a further two or more days to receive confirmed results.

Your questions answered

What happens when viral fragments are detected in wastewater?

Prolonged viral shedding periods can be a feature of COVID-19 infection, so it's not unusual to detect viral fragments in wastewater for a number of weeks after known cases are diagnosed.

If COVID-19 viral fragments are detected in wastewater, the next steps depend on whether the detection is consistent with clinical testing results in that area and the current context in Victoria. 

This could include increased or extra wastewater testing, and localised public health advice around individual testing and other hygiene and preventive measures. 

If viral fragments are detected where there are or have recently been people diagnosed with COVID-19, it is likely that no additional public health measures will be needed. The situation will continue to be monitored.

If viral fragments are detected where there have not been recent positive cases, wastewater testing will be increased to monitor trends and targeted wastewater testing may be implemented to help clarify the source. 

Previous positive results have led to boosts to local testing services and increased public health advice around individual testing, and other hygiene and preventative measures.

A repeated positive result in a local area suggests that it is more likely due to a local community member who may have COVID-19 rather than visitors to the community.

Does the detection of viral fragments in wastewater always mean there is an active case of coronavirus (COVID-19) in the area?

Viral fragments in wastewater can be due to an active infectious case but it can also be due to someone who has had COVID-19 continuing to ‘shed’ the virus. While they may not be considered infectious, it can take several weeks for someone to stop shedding the virus. The person or people shedding the virus may be local or visiting the area.

No matter where you are in Victoria, it is important that anyone with any symptoms of COVID-19, no matter how mild, gets tested. For more information on symptoms, visit the Getting tested page.

What is an inconclusive detection?

An inconclusive detection occurs when a very weak detection of viral fragments found in an initial sample is not confirmed by further analysis. These are likely to be due to someone who has had COVID-19 and is no longer infectious continuing to ‘shed’ the virus.

When there is an inconclusive detection, the frequency of testing at the site is increased. If no more viral fragments are detected, testing frequency returns to normal and no additional public health measures are needed.

If more viral fragments are detected, it is likely to lead to a boost to local testing services, increased public health advice around individual testing, and other hygiene and preventative measures.

Is wastewater testing new?

Poliovirus, norovirus and adenovirus are routinely monitored in wastewater around the world.

Other Australian states and territories are also participating in the national ColloSSoS project. The European Union has a similar active wastewater surveillance collaboration. Canada, the Netherlands, New Zealand and Turkey have also incorporated wastewater testing as part of their COVID-19 surveillance.

Will wastewater testing replace other testing for COVID-19?

No. Wastewater testing is being developed as an additional and complementary tool to the existing public health response and testing of people.

If there are viral fragments in wastewater, does this mean that recycled water or treated wastewater poses a public health risk?

No. Wastewater samples used for testing are taken at the influent (or entry pipe) to wastewater treatment plants or within the sewer network.  

Wastewater is treated to kill a wide variety of microorganisms, including viruses, before it is returned to the environment.

There is no evidence that COVID-19 can be spread via recycled water nor via treated wastewater released to waterways.

To find out more, read the Hygiene, water and sanitation for coronavirus (COVID-19) fact sheet.

Is my drinking water safe?

There is no impact on your local water supply from wastewater testing. Drinking water supplied by water utilities is safe to drink and for normal household uses.

Who is involved in the wastewater surveillance project?

The Department of Health is overseeing the Victorian wastewater surveillance program with support from Victorian water utilities in the collection of wastewater samples and our laboratory partners who analyse the samples.

Victoria is a member of the collaboration for sewage surveillance for SARS-CoV-2 (ColoSSoS). Coordinated by Water Research Australia, the ColoSSoS project brings together health departments, water utilities, laboratories and researchers from Australia and New Zealand to share advances in this rapidly evolving field.

Laboratories and researchers involved in developing wastewater sampling and testing methods include Australian Laboratory Services, the University of Melbourne, Melbourne Water, Monash University, Victorian Infectious Disease Reference Laboratory, Walter and Eliza Hall Institute, SA Water and Sydney Water. 

Further information

You can read more in the wastewater testing factsheet (Word).