Could Combined Sewer Overflows Be a COVID-19 Threat?

May 13, 2020
California has tried limiting access to beaches to reduce crowds and resulting risk of transmitting the novel coronavirus. Above, a beach closure sign on an Orange County, Calif., freeway, May 2, 2020. Photo: Russ Allison Loar, Flickr Creative Commons. Click to enlarge.

TipSheet: Could Combined Sewer Overflows Be a COVID-19 Threat?

By Joseph A. Davis

The COVID-19 virus is very contagious, which is why almost everybody wants to avoid it. But thousands still flock to the beaches when they get a chance. What could possibly go wrong?

One little-known threat that could lead to local stories for environmental journalists is the possibility of exposure to COVID-19 via overflows of untreated sewage. 

Even without the coronavirus, beaches do close when raw sewage is discharged during unusual wet-weather events. Disease-causing germs in sewage are the reason: They can and do make people sick. The coronavirus is just one more pathogen.

And yes, it has been discovered in raw sewage. And as great as modern sewage systems are, they do often fail when too much rain or snowmelt overwhelms them. When stormwater and sanitary systems are linked, they can flush untreated sewage into receiving waters — where people sometimes swim.

Doctors have found COVID-19 in stool samples from infected patients. They have also found it in raw sewage, such as that collected in Paris. This has led epidemiologists to use sampling of sewage as a measure of the rise and fall of COVID-19 outbreak intensity in particular communities. 


Why it matters

Coronavirus infection is something to avoid — the illness is awful, intubation is an extreme trauma and COVID-19 is a terrible way to die. Governors like California’s Gavin Newsom have tried to close beaches so crowds of people wouldn’t give each other the virus. But some cities have resisted. 


The risk of communicable diseases 

from recreational contact with 

sewage-polluted water is hardly a 

new thing at Southern California beaches.


The risk of communicable diseases from recreational contact with sewage-polluted water is hardly a new thing at Southern California beaches. Beach closure there is fairly common. It is a problem in other places too. There are many diseases that can be acquired by body contact with, or ingestion of, sewage-polluted water. Think cholera.

Don’t overplay the COVID-19 angle. Yes, the virus has been found in wastewater. The Centers for Disease Control, while encouraging caution, notes that there is no evidence that anyone has ever gotten infected from the virus via untreated sewage and that fully treated sewage system effluent is likely to be safe. 

The U.S. Environmental Protection Agency also notes that nobody has gotten COVID-19 from a sewage system that they know of, and that normal safety procedures and equipment for sewage system workers should also protect them from COVID-19.  


The backstory

The landmark Clean Water Act of 1972, or CWA, committed the federal government to a serious effort to end sewage contamination of public waters. In addition to regulation discharges, the law pledged federal money to help localities build sewer pipes and treatment plants. This worked pretty well, much of the time.

The problem was that, especially before 1972, stormwater and sanitary sewers were often combined or interconnected. When high water flows from big rain events flooded the sewers, treatment plants would be bypassed and overflows containing untreated sewage would spill directly into lakes, streams and estuaries. Even supposedly separated sanitary systems sometimes overflow because of upsets and unusual events.

While tens of billions of dollars were spent to build or upgrade sewage systems in the 1970s and ’80s, the program eventually ended. Upgrading the combined systems, often very old, didn’t happen because it would be very expensive. Municipalities sought a range of other solutions, such as inline storage.

Since the 1980s, the EPA has had a program for controlling combined sewer overflows as much as practical. Every municipal wastewater system has a permit for its discharges under the CWA, and the National Pollutant Discharge Elimination System, or NPDES, of permits has been a main tool for lowering combined sewer overflows, or CSOs. It gets complicated, but you can read more about it here.

The EPA’s CSO policy emphasizes easier solutions, rather than laying whole new pipe systems that municipalities often can’t afford. For example, physical equipment to remove floatable and screenable materials from the effluent, or making sure that industries pay for and implement pretreatment of the wastes they might discharge.      


Story ideas

  • Is anybody testing for COVID-19 in your local untreated sewage? How much lab capacity does your system have? Have any area public health researchers gotten involved? Check at local agencies and academic institutions.
  • What water bodies in your area are sometimes closed for swimming or recreation because of sewage-related closures?
  • What are the main parts of your local sewer system that are responsible for CSOs? What are the plans for improving the situation? 
  • What are the CSO notification requirements for your area? How are notifications disseminated? Are there signs at your local beach?
  • What procedures and equipment are used at your local sewage treatment plant to protect workers from infection generally?


Reporting resources

  • State list of impaired waters. The CWA requires each state to publish every two years a list of “impaired waters” that do not meet CWA standards. The publication does not always go smoothly. But the list provides a good roll-call of suspects for CSO and sanitary sewage discharges. Look here.
  • NPDES permits and violations. Permits are public documents and therefore valuable grist for investigative reporting. Your local municipal sewer system has one. They can be found in several databases at the state and federal levels. Most useful may be EPA’s ECHO database, online and searchable, which gives a history of violations.
  • Waterkeeper Alliance. This network of local nonprofit, nonpartisan, citizen organizations consists of watchdogs who know where the … er, bodies are buried. You can find the one that watches over your local water body of concern here.
  • State water pollution control agency. Just about every state, territory or tribe has its own agency responsible for carrying out CWA requirements under EPA supervision. Most have information officers who will talk to you. Find yours via this directory.
  • Local sewerage agency. Every municipality (or unincorporated area) is a little different, but there is an agency that runs your sewage system, if you have one. Talking to them is a must. You might start by looking at the letterhead on your water and sewer bill.

Joseph A. Davis is a freelance writer/editor in Washington, D.C. who has been writing about the environment since 1976. He writes SEJournal Online's TipSheet, Reporter's Toolbox and Issue Backgrounder, as well as compiling SEJ's weekday news headlines service EJToday. Davis also directs SEJ's Freedom of Information Project and writes the WatchDog column and WatchDog Alert.

* From the weekly news magazine SEJournal Online, Vol. 5, No. 19. Content from each new issue of SEJournal Online is available to the public via the SEJournal Online main page. Subscribe to the e-newsletter here. And see past issues of the SEJournal archived here.

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