Is coronavirus hiding in your sewage system? | COMMENTARY

Past studies in public health have demonstrated an association between disease and poor sanitation, such as illnesses from exposure to sewage-laden waters. Modern sanitary infrastructures were an innovation that transformed how we mitigate waterborne risks.

However, failure to maintain and rehabilitate these systems over the years, as well as changing environmental conditions, have created some pre-modern circumstances in cities across the world including Baltimore, which has frequent sanitary sewer overflows (SSOs) due to an aged and declining system and more frequent and intense rainfall events further overwhelming the system.


These risks may be particularly evident in marginalized urban neighborhoods that often bear the brunt of infrastructure in disrepair. To add another layer of concern, Baltimore City has the fourth largest number of COVID-19 related cases by county in the state of Maryland which if/when intersected with SSOs and backups can have some notable risks to ecological and public health.

Poorly constructed and maintained wastewater infrastructure can lead to sanitation-related health risks in urban areas. Sanitary sewer systems are designed to collect and transport domestic, commercial and industrial wastewater through an underground piped network for appropriate treatment and then deposited into local waterways. Occasionally, sanitary sewers will release raw sewage, particularly when additional waters enter and overwhelm these systems like during a heavy rainfall event, which will uptick during hurricane season.


According to the U.S. Environmental Protection Agency (EPA), SSOs can contaminate our waters, causing serious water quality problems, and back up into homes, causing property damage and threatening public health. There are 13 diseases that have been transmitted by water including hepatitis A, Legionnaires’ disease and cholera, according to the Centers for Disease Control and Prevention. Might we add COVID-19 to that list?

The virus that causes COVID-19 has been found in the feces of some patients diagnosed with it and thus in untreated wastewater, according to the CDC. It is unclear whether the virus found in feces may be capable of causing COVID-19. Researchers do not know, due to lack of evidence, whether this virus can cause disease if a person is exposed to untreated wastewater or sewage systems. It is also unclear how much risk there is that the virus could be spread from the feces of an infected person to someone else, although it is likely low based on data on related coronaviruses, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), CDC research has found.

Nevertheless, even if the risk of direct spread of COVID-19 is low, when you compound known waterborne infections related to sanitary sewer backups and overflows with the current coronavirus pandemic, compromised gastrointestinal and respiratory systems can complicate health impacts if infected with COVID-19. And earlier evidence has demonstrated that Black communities are particularly at a greater risk of mortality from COVID-19 because of other preexisting conditions.

One study suggests, symptoms of waterborne illness are primarily gastrointestinal, but upper respiratory and skin manifestations also occur, some causing morbidity and mortality. Another study demonstrated that waterborne diseases contribute to 500,000 U.S. treat-and-release emergency department visits and hospitalizations annually at a cost of nearly $4 billion each year.

According to a report by the Chesapeake Bay Foundation, from 2011 to 2017 there were more than 3,900 individual sewer overflow events in the city spilling more than 110 million gallons of sewage into the streets, homes, streams and rivers of Baltimore and eventually the Chesapeake Bay. Historically, most outbreaks of waterborne illnesses in the U.S. could be traced to individual wells or smaller community systems, but due to more frequent and intense rainfall events as a result of a changing climate, rapid urbanization and increased amounts of impervious cover, human and animal waste and pollution, and declining infrastructure, these incidents have made their way back to urban settings.

The problem of contaminated waters and surfaces, and related disease will only worsen unless measures are taken in the immediate future to assess sanitary risks and microbial exposures associated with stormwater and waste management at the nexus of natural, built and human systems. Efforts also have to be made to identify vulnerable and overburdened populations and apply appropriate interventions to support these specific communities.

Marccus D. Hendricks ( is an assistant professor of urban studies and planning at the University of Maryland.