UPDATED: April 15, 2021. This article was originally posted on March 27, 2020, and is updated as more information becomes available.
As communities across the country experience the threat and disruption from COVID-19, many are wondering what they can do to keep themselves and their families safe. In addition to practicing social distancing, washing hands and spending more time at home, those of us in coastal communities may also seek the solitude, solace and maybe even a wave or two at our local beach. But does spending time in coastal waterways increase your risk of getting sick?
To help answer this question, Surfrider is working to stay abreast of emerging science and community concerns to keep the beachgoing public as informed and safe as possible. Please note that there is still high uncertainty and this research is ongoing, so information presented below is only current as of April 15, 2021.
While there are still notable research gaps, the general consensus is that the COVID-19 virus might be transmittable through the “fecal-oral route”. This means that recreating in sewage polluted waterways could put you and your loved ones at risk of getting sick from a wide range of fecal-borne illnesses in addition to, potentially, COVID-19. Though that risk is considered low due to the rapid inactivation of SARS-CoV-2 in recreational waterways. As always, please check your local beach water quality before heading to the beach. Fortunately many beaches are tested for the presence of fecal indicator bacteria by local agencies and citizen scientists. To access your local beach water quality and see if any advisories are in place, click here. Research on the potential for transmitting COVID-19 through sewage-polluted beach water is currently underway, and we will post updates as soon as results become available.
What do we know about the virus?
COVID-19 is a highly contagious disease that started in China but is now considered a global pandemic. The disease is caused by the coronavirus, SARS-CoV-2, which is closely related to other viruses in the coronavirus family that cause respiratory illness and can transfer between species. With seven known coronaviruses, much of the information we have on this virus is from previous research on other coronaviruses assumed to exhibit similar behavior, but research specific to the COVID-19 virus is underway. For now, we know the virus spreads from close, person-to-person contact, mainly through respiratory droplets in the air (after a sneeze, cough, or exhale). It’s been documented in all 50 states, and symptoms appear within 2 to 14 days from exposure (though there are also many asymptomatic cases). Fortunately the virus is enveloped, meaning it’s highly susceptible to chlorination - so chlorine and bleach are effective at disinfecting contaminated surfaces and water sources.
Does the virus spread through recreational waterways?
A March 2021 Study is the first to publish results about the viability of SARS-CoV-2 in seawater, confirming that the virus can in fact remain viable and infectious in seawater, but just for one to two days pending on water temperature. Lower temperatures resulted in a longer decay rate than higher temperatures. The same study found that the virus can remain infectious in river water for slightly longer, ranging from two to four days pending water temperature. Similar coronaviruses have been shown to remain viable and infectious in natural freshwater environments including lakes and streams, for up to 13 days at 77°F and over 14 days at 40°F (this study only lasted for 14 days and on the last day there was still no reduction in infectivity for one of the coronaviruses tested). To note, both of these studies used water samples pulled from natural environments but were then spiked with the virus in a laboratory environment to test the viral decay rate. In the natural water body, dilution and exposure to other factors (UV, organic substances, other microorganisms) would alter the risk and duration of infectivity (Bilal et al 2020). As such, authors of the 2021 study concluded that the “rapid inactivation” of infectious SARS-CoV-2 in seawater and river water indicate that the likelihood of contracting COVID-19 from swimming at sewage-contaminated saltwater and freshwater beaches is low.
How could the virus even get into recreational waterways?
Like many harmful viruses and pathogens, the main exposure risk to the water recreation community is from sewage pollution. The release of raw or undertreated sewage into our surface waterways can cause diseases to spread through the “fecal-oral transmission route.” In other words, when we recreate at the beach during a sewage spill or release of undertreated wastewater, we risk ingesting fecal-borne pathogens that can cause symptoms like stomach upset; ear, eyes, nose and throat infections; as well as more severe infections like E. coli, MRSA, giardia, hepatitis, and worse.
At this point, the research community does not know if people can contract COVID-19 from exposure to feces in recreational waters but the overall consensus is that it might be possible. A July 15 2020 paper in Water Research nicely summarizes the available research at that time, and highlights that there are still notable unknowns when it comes to the potential for fecal and recreational water transmission. For instance, the RNA of the virus was found in stool samples of infected patients, but we do not know if the virus remains infectious after passing through the human digestive system. In order to be infectious, the virus needs both intact RNA and an intact outer envelope. No published study has yet to confirm the presence of an intact outer envelope extracted from stool or sewage. A recent study out of Germany indicates that the virus is not infectious after passing through the digestive system. Meanwhile, authors of a different study out of China mention that they have been able to isolate the viable, infectious virus from stool, yet this was from “unpublished data”, so additional confirmation is needed to validate their statement. Other studies point to the virus behavior in the GI tract as potential evidence for the ability of fecal-oral transmission (see Diaz & Taboada 2020 Ghoshal et al 2020, and Leo et al 2020), and its similarity to the SARS-CoV-1 virus (Oliva et al 2020).
There is also reporting that speculated on the potential for the virus to become aerosolized in sea spray when polluted waterways are actively churned or agitated (such as when a wave breaks), but this is currently just speculative since we don’t know if the virus is infectious in sewage, or how it behaves after “exposure to air, sunlight, and water”.
The potential for sewage to contain the infectious COVID-19 virus is of particular concern to areas that experience persistent spills and releases of raw sewage, such as coastal communities along the US/Mexico border. Since infected individuals are able to shed the virus in their stool for up to five weeks after recovering from the disease, additional research is severely needed to confirm this potential transmission route. Fortunately, a study to determine if the infectious COVID-19 virus is actually present in sewage-polluted coastal water and able to aersolize in sea spray, submitted by Dr. Kim Prather from Scripps Institution of Oceanography, was recently awarded funding by the National Science Foundation, and is currently underway. Dr. Richard Melvin also recieved funding from Sea Grant in July 2020 to conduct his research project titled Monitoring the Presence of SARS-CoV2 Virus in Surface Waters Connected to Public Recreation Sites.
Due to the current uncertainty, areas severely-affected by sewage spills, leaks or overflows, or have high numbers of septic tanks, cesspools or homeless populations, could have increased risk for potential transmission of the virus in affected waterways. Local health authorities post warnings to protect public health from exposure to many different harmful pathogens in sewage that can make you sick. Surfrider’s Clean Water initiative strives to protect clean water and to eliminate these sources of pollution that can put public health at risk. Note that cities have predominanly re-opened beaches as stay-at-home orders were lifted. Popular public spaces, including beaches, were temporarily closed to help prevent the spread of COVID-19 (due to concern about the potential elevated likelihood for person-to-person contact). As always, Surfrider urges you to check your local beach water quality before heading to the beach, as high bacteria is an indication of raw or undertreated sewage in the water. Even if recreating in sewage-polluted waterways is determined not to be a transmission route for COVID-19, it could still expose you to other pathogens which could tax your overall immune system.
Do sewage treatment practices remove or disinfect the virus?
Typical treatments that include sterilization with chlorine and other disinfectants are expected to be highly effective at eradicating the virus. However, if you are in a place that uses only primary treatment at your sewage treatment plant, it could be possible that the viable virus might be discharged with effluent into waterways through offshore outfalls or groundwater injection wells. Studies estimate that if the live virus enters the wastewater stream, it can remain viable in wastewater for hours (Hart & Halden 2020) to days (Barcelo 2020), and might become airborne when aerosols are released during treatment. Other researchers noted some concern about biosolids, which are waste solids from treatment plants used as fertilizer, being able to accumulate viruses and other pathogens if not treated to Class A standards, but no literature was provided to confirm this potential risk. In the meantime, to keep wastewater systems functioning properly and therefore prevent potential raw sewage exposure to maintenance staff, the EPA asks that people flush only toilet paper (no flushable wipes!) and avoid dumping grease down drains. Conserving water in your home and minimizing the amount of water that goes down the drain also helps keep wastewater systems from being overloaded.
What are best practices to stay safe?
The CDC keeps an updated list of best practices to stay safe. Researchers stressed the fact that community mitigation is key and everyone has a role to play to protect themselves and others. Some key steps include:
Wash your hands for at least 20 seconds frequently and thoroughly
If soap and water are not available, use at least 60% alcohol-based hand sanitizer
Do not touch your face (especially eyes, nose or mouth) with unwashed hands
Clean frequently touched surfaces often with home cleaning products and then follow with disinfectants that contain either adequate concentrations of bleach or are minimum 70% alcohol-based. Note that you can easily make your own disinfectant for surface cleaning by mixing 4 tsp bleach per 1 quart of water.
Absolutely stay home if you are sick
Practice social distancing and avoid indoor gatherings
If you choose to go to the beach, check current swim advisories and water quality conditions in your area
Visit this CDC website for daily practices to keep you and your community safe
There’s a lot we don’t know. Please use the following trusted resources to stay up to date.
Everything is happening quickly and the truth of the matter is we don’t know a lot about this virus. Surfrider recommends caution and encourages communities to stay abreast with the latest information and research as things are changing rapidly and ongoing research provides new results: