COVID-19 wastewater testing

The Wastewater Surveillance Program tests untreated sewage from treatment plants for fragments of SARS-CoV-2 across the State.

Samples are taken from six metropolitan locations: Alkimos, Beenyup, Gordon Rd, Point Peron, Subiaco and Woodman Point. In addition, there are also 10 regional localities where testing is conducted: Albany, Broome, Bunbury, Busselton, Esperance, Geraldton, Kalgoorlie, Karratha, Northam, South Hedland.

A wastewater detection of viral fragments in an area that is unexpected will trigger a public health response.

The dashboard displays results of weekly wastewater test results for metropolitan and regional areas.

Explanation of results

Not detected: The presence of SARS-CoV-2 has not been detected in the sample.

Expected detection: The presence of SARS-CoV-2 has been detected in a sample from this area, which has known COVID-19 cases (e.g. quarantine hotels with returned international travellers) and this result is expected.

Unexpected detection: The presence of SARS-CoV-2 has been detected in a sample from this area, which is not known to have COVID-19 cases.

Invalid: Inhibitors within the sample means the presence of SARS-CoV-2 cannot be excluded.

COVID-19 wastewater testing in the community

Can I get coronavirus (COVID-19) from wastewater?

No. Current evidence shows that the virus cannot be spread through wastewater.

Will wastewater testing replace other types of testing for coronavirus (COVID-19)?

No. Wastewater testing will complement – but cannot replace – other kinds of COVID-19 testing, including nose and throat swabs. This is because wastewater testing does not tell us if an individual has COVID-19, only that it may be present in the broader community.

It is important that anyone who develops symptoms of COVID-19 (e.g. fever, cough, sore throat, runny nose, loss of taste or smell) is tested and isolates until they get their result.

How can coronavirus (COVID-19) be detected in wastewater? 

People who have had coronavirus (COVID-19) normally shed the virus when they do day-to-day activities like blowing their noses and going to the toilet. People can continue to shed the virus for several weeks after they recover from COVID-19, even when they are no longer infectious. The virus enters wastewater through drains and toilets, and travels through the sewerage network as viral fragments.

Does a wastewater detection always mean that there is an active case of COVID-19 in that community?

No, not necessarily. While detection of SARS-CoV-2 viral fragments in wastewater may be from a person in the early and infectious stage of coronavirus (COVID-19), it could also be from someone who has fully recovered from COVID-19 and is no longer infectious but is still shedding the virus. People can shed the virus for weeks after they recover from COVID-19. A wastewater detection could also be from a visitor or someone passing through the community who is no longer present in the community.

What are the samples used for?

The samples will be tested for viral fragments of SARS-CoV-2, the virus that causes coronavirus (COVID-19). The findings may provide an early warning of undiagnosed COVID-19 in the community. Specifically, samples may detect COVID-19 in the community that either hasn’t yet been diagnosed, or from people who have recently recovered from the disease and are no longer infectious.

In some cases, detection of viral fragments in wastewater may lead to more wastewater testing, or changes to public health advice (like asking community members to get tested for COVID-19).

COVID-19 wastewater testing program

People can shed the SARS-CoV-2 virus – the virus that causes coronavirus (COVID-19) – in their faeces (poo) and mucus (snot and phlegm). When these are flushed down toilets or drains the virus enters the wastewater system and breaks apart into ‘viral fragments’. The wastewater testing program aims to detect the SARS-CoV-2 viral fragments in samples of wastewater.

The viral fragments from SARS-CoV-2 are not infectious, but detecting them in wastewater may show that there is undetected COVID-19 in a community. The wastewater testing program complements other work already being done to monitor COVID-19, including testing of individual people using nose and throat swabs, and, together, these help inform WA Health’s response to the pandemic.

The Wastewater Surveillance Program tests untreated sewage from treatment plants for fragments of SARS-CoV-2 across the State.

Samples are taken from six metropolitan locations: Alkimos, Beenyup, Gordon Rd, Point Peron, Subiaco and Woodman Point. In addition, there are also 10 regional localities where testing is conducted: Albany, Broome, Bunbury, Busselton, Esperance, Geraldton, Kalgoorlie, Karratha, Northam, South Hedland.

COVID-19 wastewater testing programs are being run across Australia, but because these programs are new there are many questions that need to be answered. To address these questions, a national research group called the Collaboration on Sewage Surveillance for SARS-CoV-2 (ColoSSoS) (external site) has been formed. It will help Australian states and territories share information and experiences about their wastewater testing programs.

WA's COVID-19 wastewater testing program steering committee

The WA Department of Health is overseeing the pilot wastewater testing program with support from Water Corporation and PathWest Laboratory.

WA Health has set up a steering committee to:

  • identify target populations
  • provide information about high risk populations
  • guide the public health response if a wastewater detection occurs
  • calculate the cost of the program and understand the resources involved
  • understand how the wastewater surveillance complements clinical surveillance systems (e.g. taking swabs from individuals for COVID tests).

The steering committee includes representatives from the WA Health’s Environmental Health Directorate (EHD) and the Public Health Emergency Operations Centre, WA Country Health Service, the Water Corporation, and PathWest.

Last reviewed: 07-05-2021