Updated Info: What’s Known About Chlorine’s Impact On Coronavirus

In March of 2020, the World Health Organization (WHO) declared the coronavirus (COVID-19) as a global pandemic. At the time, little was known about the structure of the virus, how it spread, or what types of conditions made contagion more or less likely.

During that same timeframe last year we published an article conveying what data was known specifically regarding chlorine‘s impact on the coronavirus. The article wound up being SwimSwam’s most-read post of 2020.

As we relayed at the time, Ireland’s Health Service Executive, essentially the equivalent of the Department of Health & Human Services in the United States, confirmed that the coronavirus cannot be transmitted in drinking water and swimming pools, provided these mediums are properly chlorinated.

As we enter 2021 with the coronavirus having been present in about everybody’s lives for just under a year, more studies have been conducted and more robust knowledge has been accumulated regarding everything from symptoms to strain variations to transmission. As such, additional data has been gathered specifically to water-based environments and their impact on coronavirus.

World Health Organization (WHO)

On July 15, 2020, the WHO released its study results pertaining to its investigation of 3 main areas 1) coronavirus persistence/survival in water; 2) coronavirus occurrence in water environments, and 3) methods for recovery of coronavirus from waters.

Its study concluded that coronavirus ‘seems to have a low stability in the [water] environment and is very sensitive to oxidants, like chlorine.’ Additionally, coronavirus appears to be ‘inactivated significantly faster in water than non-enveloped human enteric viruses with known waterborne transmission.’

According to the WHO‘s study results, coronavirus‘ resistance to chlorine is lower than for bacteria. ‘It follows that the current water disinfection practices (drinking water, wastewater, water from swimming pool), effective against non-enveloped viruses and bacteria, are expected to be effective also towards enveloped viruses such as coronaviruses.’

United States’ Centers for Disease Control (CDC)

On the Centers for Disease Control website, whose updates are current through December 31, 2020, the organization states, ‘CDC is not aware of any scientific reports of the virus that causes COVID-19 spreading to people through the water in pools, hot tubs, or water playgrounds.’

‘Plus, proper operation of public pools, hot tubs, and water playgrounds (such as at an apartment complex or owned by a community) and disinfection of the water (with chlorine or bromine) should inactivate the virus.’

U.S. National Center for Biotechnology Information

Researches at the U.S. National Center for Biotechnology Information published another aquatic environment study in October of 2020.

In its study evaluating favorable conditions for the survival of coronavirus (SARS-CoV-2) in aquatic environments, the NCBI confirmed again that the coronavirus‘ survival in an aquatic environment is strongly dependent on the actual characteristics of the water itself.

The report points to studies suggesting that coronaviruses are very sensitive to high temperature and oxidants such as chlorine.

Swimming Canada Member Data

Last October, Swimming Canada’s coronavirus management assessment group reported data gleaned from both high-performance centers, as well as non-HPC training hubs around the nation.

The 4 HPC centers of Ontario, Vancouver, Victoria, and Quebec conducted a total of 4,065 combined training sessions involving 46 athletes from the time swimming resumed in the summer through September 30th. Across this time frame, there had been zero COVID-19 positive tests from the Swimming Canada athletes and staff at HPCs.

Additionally as of September 30th, 157 head swimming coaches from Canada’s 460 clubs reported through the Swimming Canada survey on their clubs’ coronavirus data. With 14,000 swimmers returning to training at these clubs over the course of 167,000 individual training sessions, there were no reports of COVID-19 spread at the pools. The same held true for swimmers at Canadian Universities. In total, with 282,000 individual training sessions completed, there has not been any recorded/reported transmission at a club or university swimming training session.

New Jersey Swim Safety Alliance

As we reported last November, the New Jersey Swim Safety Alliance (NJSSA), a group that formed to lobby the state’s governor to reopen indoor pools in June of 2020, said that a survey has shown no reported results of coronavirus infections at indoor pools throughout the state.

According to a press release, 44 facilities reported 212,641 people coming through their indoor pools with 0 infections in their facility.

It’s important to note that this was a voluntary survey, and is not considered to be scientific, though it has become one of the most-cited pieces of data in the battle to reopen, or keep open, pools around the world.

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1 year ago

Does anyone know the lane restrictions in place in Canada or NJ?

1 year ago

Data from Connecticut high school sports in the fall showed that girls’ swimming had the lowest rate of both covid-19 positive tests and team quarantines of any sport during the season. Only 2.35% of girls’ high school swim teams had a positive test and 8.24% of teams were forced to quarantine (usually due to non-sports exposures).

That lines up with the data collected by CT Swimming clubs that show extremely low case counts from when sports were allowed to restart in June through when the governor shut sports down again in November. Being immersed in chlorinated water and following the USA Swimming protocols for practice obviously works.

Sports are still shut down until the 19th at the earliest,… Read more »

1 year ago

Retta, please send this article to No.10 Downing St.

1 year ago

One thing I did when I got out of the pool after my first four hour shift, was not shower, so the chlorination effect would last longer. I would shower at the end of the day. If I had to run an errand after teaching, I wouldn’t shower until I got back. I figured that if I left the residual chlorine on me, it would protect me and maybe prevented some spread. I still wear a mask, but I wrote “Punish China” on the front. They need to be held accountable for this mess.

B Nord
1 year ago

Many water districts disinfect the water with chloramine, rather than chlorine only. Have any studies been done on the effects of chloramine on the covid virus?

1 year ago

Finally! A reason to drink pool water! I can finally cleanse my insides of the coronavirus.

Reply to  Khachaturian
1 year ago

You and DJT!

Chuck Warner
1 year ago

Thank you for this article Retta. Updated NJSSA Survey numbers are over 70 pools reporting nearly 400,000 visits from swimmers and their chaperones, with 0 transmission of C19 within their facilities (ie, from swimmer to swimmer, staff to staff or parent to parent).

1 year ago

And Whitmer has all but destroyed club swimming in Michigan. Kids flocking to southern states to find pools. They both use “ follow the science” but only when it supports their narrative! Horrible people

Reply to  John
1 year ago

1000% correct

Reply to  Doconc
1 year ago

Love how we are getting negative feedback when the whole article proves our point. It doesn’t survive well in water and even less in chlorinated pool water.

About Retta Race

Retta Race

Former Masters swimmer and coach Loretta (Retta) thrives on a non-stop but productive schedule. Nowadays, that includes having just earned her MBA while working full-time in IT while owning French 75 Boutique while also providing swimming insight for BBC.

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