Claims have been made that simply being in sea water near a beach exposes you to the possibility of COVOD-19 infection:

In a Los Angeles Times interview early last week, [Kim] Prather was quoted as saying, “I wouldn’t go in the water if you paid me $1 million right now.” She posited that SARS-CoV-2, the virus that causes COVID-19, could enter the ocean — through raw or poorly treated sewage — and then get kicked back into the air along the surf zone.

Prather later walked back her statement, saying that ordinary polluted water was the problem, regardless of the virus. But the COVID/sea water claim is still being bounced around on the internet.

It seems to me that any virus that gets into sea water would be rapidly deactivated, if not by the salt water itself then by the pollutants in the water and sunlight. Plus getting greatly diluted virus particles out of the water and into the air in sufficient quantities to represent a significant risk seems unlikely.

So is there any reasonably significant probability that COVID-19 virus particles could be "washed" into sea water and then somehow aerosolized in sufficient quantities to represent a hazard to a person on the beach or in the water?

  • don't swim near the sewage, just in case dutchwatersector.com/news/… – SX welcomes ageist gossip Apr 19 at 0:42
  • @Fizz - I gather you didn't read the article. The testing detected fragments, and they are doing this testing to try to track the progress of the disease. The article does not mention swimming. – Daniel R Hicks Apr 19 at 0:51
  • Yes I did read it "The method does not discriminate between inactive and infectious particles." That doesn't guarantee the "fragments" are not fully active viruses. – SX welcomes ageist gossip Apr 21 at 1:09
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    I've added the US tag since the q was about the US beaches and the [CDC] answer might not apply to poor countries that don't chlorinate their wastewater. – SX welcomes ageist gossip Apr 21 at 12:43
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    @Fizz - It should be noted that he says those are viruses that infect bacteria, and are completely harmless to humans. – Daniel R Hicks Apr 21 at 17:16

The information on waterborne transmission provided by the US Centers for Disease Control suggests that this is very unlikely.

It states:

There is no evidence that COVID-19 can be spread to humans through the use of pools, hot tubs or spas, or water playgrounds. Proper operation, maintenance, and disinfection (e.g., with chlorine and bromine) of pools, hot tubs or spas, and water playgrounds should inactivate the virus that causes COVID-19.


At this time, the risk of transmission of the virus that causes COVID-19 through sewerage systems is thought to be low. Although transmission of the virus that causes COVID-19 through sewage may be possible, there is no evidence to date that this has occurred. [...] The available information suggests that standard municipal wastewater system chlorination practices may be sufficient to inactivate coronaviruses, as long as utilities monitor free available chlorine during treatment to ensure it has not been depleted.

Ocean water is not addressed directly but taken together I think this information raises enough reason to doubt that Prather's statement accurately describes a known risk.

EDIT: Here is a relevant publication from the WHO. It similarly states that good sewage practices are important but that "there is no evidence about the survival of the COVID-19 virus in drinking-water or sewage." Neither source, nor any other credible source that I've seen, implies that seawater or other salt water may be different in this regard.

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    I almost answered with this info too, but then I realized the ocean is not chlorinated. Yeah, it has salt, but if that were enough to kill germs quickly, we would not bother with the more expensive chlorination. (In fact even salt-water pools are chlorinated, by a somewhat different process than sweet-water pools.) So to be more convincing, this answer would have to show that salty water is almost as good as chlorination as far viruses go. – SX welcomes ageist gossip Apr 21 at 0:58
  • Dilution (in the vast ocean) would probably be a more convincing argument. Except we don't seem to know what the MID (minimum invective dose) for Covid-19 is. For some viruses the MID is [strongly suspected] to be just one virion! – SX welcomes ageist gossip Apr 21 at 1:04
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    The ocean isn't chlorinated and that ocean salt doesn't kill viruses that doesn't seem to matter as long as the sewage is chlorinated. Dilution is also relevant, although people do get sick from ocean water when sewage is not treated correctly. – Brian Z Apr 21 at 11:38
  • Indeed "The US Centers for Disease Control and Prevention has recorded a number of cases of shigellosis outbreaks caused by the consumption of freshwater shellfish harvested from waters contaminated by wastewater effluent." chlorine.americanchemistry.com/Chlorine/Wastewater-Chlorination – SX welcomes ageist gossip Apr 21 at 12:37
  • "Natural decomposition processes would normally reduce these pathogens due to decay, predation and dilution. However, increasing human populations and discharge of effluent into receiving waters have limited the natural capability of self purification, making it necessary to disinfect the effluents before they are discharged." – SX welcomes ageist gossip Apr 21 at 12:38

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