As the nation continues to navigate its way through the Coronavirus Disease (COVID-19) pandemic, we wanted to pass along some updated information from the Centers for Disease Control and Prevention (CDC) and the U.S. Environmental Protection Agency (U.S. EPA). Our blog post from March 19, 2020, remains a good primer on COVID-19 and drinking water, but there are a few updates to provide amid what appears to be an uptick in speculation about the transmission of the virus in sewage.
Two researchers at the University of Minnesota plan to study whether the virus is capable of traveling from wastewater to drinking water. Although they believe that most public drinking water supplies are safe, they posit that a risk could accompany situations where wastewater gets into private wells or public water supplies in a limited number of cities that do not disinfect their water supplies with chlorine. However, the researchers have already commented that they are not expecting to find any problems with drinking water in places where residents are connected to city sewer and water treatment systems.
There have been past studies (e.g., concerning SARS) that have concluded “coronaviruses can remain infectious for long periods in water and pasteurized settled sewage, suggesting contaminated water is a potential vehicle for human exposure if aerosols are generated.” It is important to note though that those studies did not find that a person could be infected under normal conditions when exposed to water.
Since our last update, the CDC has reported that the virus “has been found in untreated wastewater.” But the CDC is reporting “Researchers do not know whether this virus can cause disease if a person is exposed to untreated wastewater or sewerage systems,” and that “there is no evidence to date that this has occurred.” The CDC states that “Researchers have analyzed the available information which suggest that standard municipal and individual septic system wastewater treatment practices should inactivate the virus that causes COVID-19.” The CDC continues to review information on COVID-19 transmission as it becomes available.
Separately, the CDC states the virus has been detected in the feces of some patients that have been diagnosed with the disease. But it is not known whether the virus in stool can cause COVID-19, and there have been no confirmed reports of the virus spreading from feces to a human. The CDC is also reporting though that scientists “do not know how much risk there is that the virus could be spread from the feces of an infected person to another person,” but that the risk “is expected to be low based on data from previous outbreaks of related coronaviruses, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).”
The CDC’s position remains that COVID-19 has not been detected in drinking water, and that conventional water treatment methods that use filtration and disinfection (like those found in most municipal drinking water systems) should be effective in removing or inactivating the virus that causes COVID-19.
Similarly, the U.S. EPA’s advice remains that “Americans can continue to use and drink water from their tap as usual.” The EPA cites the World Health Organization (WHO), which states the “presence of the COVID-19 virus has not been detected in drinking-water supplies and based on current evidence the risk to water supplies is low.”