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Is the transmission of Covid-19 possible through sewage systems?

Members of the WhatsApp community have been warned of the risks in contracting the Covid-19 virus through their sewage systems, connected to their homes through bath tubs, toilets and drains.

This would by extension render even those in isolation and self-confined individuals at risk of contracting the deadly disease.

The message reads thus:

Image Source: WhatsApp


Claim 1: Dutch Authorities found the virus in sewage systems.

Mostly true. Although the Dutch study found the coronavirus within their sewer system, there was no mention of the virus growth and multiplication within the study.


A study conducted on sewage samples from seven(7) cities and the airport in the Netherlands on the presence of coronavirus in sewage discovered that the virus that causes the Covid-19 disease was present in wastewater. This study was the first report of detection of SARS-CoV-2 in sewage.

What does finding the virus in sewage mean?

This means that one or more people in the community likely excreted the virus through urine, faeces or by coughing or sneezing. This is detected through molecular tests such as polymerase chain reaction (PCR) tests which can detect the presence of the SARS-CoV-2 virus via fragments of genetic material (RNA) in wastewater.  

Claim 2: Covid-19 can be transmitted through exposure to wastewater.

Insufficient evidence. The WHO says there is no evidence that Covid-19 has been transmitted through sewerage systems. Some studies however suggest transmission may be possible under certain conditions. 


According to information accessed on March 9th, 2021 on the updated questions and answers section of the World Health Organization (WHO) website, there is no evidence that the COVID-19 virus has been transmitted through sewerage systems.

However, some studies, including one by Amoah, Kumari and Bux (2020), found that exposure to untreated wastewater within those two days after viral shedding may lead to potential infections. This study also highlights the potential risk of infection for workers in wastewater treatment facilities and even in the public through faulty plumbing and bursting of sewer networks.

People who work with sewage have therefore been advised to avoid direct contact with sewage and to avoid ingesting, swallowing, or inhaling spray or mist from the water as it contains various pathogens.

Claim 3:  Covid-19 in sewerage systems can be curbed by pouring bleach into drains and other sewage outlets.

Insufficient evidence. High concentrations of disinfectants in wastewater can destroy the coronavirus because of the fragile outer membrane of the virus. Research however indicates that doing so  may jeopardize scientific research and affect the treatment plants. 


Many chemical disinfectants like bleach work against the novel coronavirus, but it is important to use them properly and never ingest them or apply them to your skin.

The Centers for Diseases Control and Prevention (CDC) and the World Health Organization recommend using a bleach solution as a way to disinfect areas contaminated with the novel coronavirus. It is however unclear whether the use of bleach in drains and toilets can completely eradicate the virus. Studies indicate that wastewater treatment processes can inactivate the virus in the wastewater but this is mostly on a larger scale. Individually, disinfectants used in home drains can support removal of the virus from the direct tubes and drains but reports also suggests that  the use of bleach may also cause a stall in scientific research on the virus as bleach will kill the ribonucleic acid(RNA) of the virus. 

Can wastewater find its way into your home?

Yes. Waste material can find its way into homes. This is called a sewer backup; this happens when water is pushed back into homes through pipes from the sewer or drainage systems. Backups can be caused by clogging or blockage of a city’s mains or a building’s plumbing system , old sewer systems etc. For instance, flushing materials like diapers or sanitary towels in toilet bowls has the potential of causing a blockage and possibly a backup. 

This occurrence is potentially dangerous as it can cause infections or diseases because it lets off air-borne contaminants as well as physical contaminants. The inhalation of the vapors alone is dangerous as toxins are released into the air. Additionally, some diseases can be caused from bacteria, viruses and parasites that may surface because of sewer backups like salmonellosis, gastroenteritis, threadworm infection, hookworm infections among others. Proper maintenance of the sewage system is necessary to avoid such incidents. 

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