2008 Uni of Arizona Research Called For More Study Into Survival Of Coronavirus in Water [UPDATED March 11 – Link To CDC Guide]


Research conducted at the University of Arizona more than 12 years ago has raised questions about whether the new coronavirus COVID-19 strain behind a global health emergency could be transferrable through water in the way that stomach ‘flu and other more common viruses are, Swimming World reported on February 27, 2020.

That story in full is below three updates to the file since:

Update:  Further to our February 27 article pointing to research into the relationship between the Coronavirus (COVID-19) and water as far back as 2008, questions remain and caution is recommended by leading health organisations and relevant industry experts when it comes to how the virus can be transmitted.

March 11: some questions have now been answered today:

Water Transmission and COVID-19

Previous updates:

March 10 update:

The Pool Water Treatment and Advisory Group (PWTAG) of Great Britain is working with Public Health England on the significance of novel coronavirus, water, pools and swimmers/

A spokesperson for PWTAG said:

“Public health opinion is that it is generally safe to go swimming at this time. Water and the chlorine within swimming pools will help to kill the virus. However, visitors to swimming pools are reminded to shower before using the pool, to shower on leaving the pool and to follow the necessary hygiene precautions when visiting public places to help reduce the risk of infection.”

March 4 Update:

Health authorities continue to urge caution when it comes to whether water can help transmit coronavirus (COVID-19), although water treatment companies are posting notices on company websites declaring that the virus at the core of a global health emergency “can be disinfected through use of ozone, chlorine and other treatment processes used in processing your tap water”.

While the latter appears to provide comfort for pool swimmers in narrow terms of the risk the actual water may pose, the European Centre For Disease Prevention And Control warned against complacency in the following terms:

“The rate at which a person can get COVID-19 by touching a contaminated surface or object (i.e., fomites) and then touching their own mouth, nose, or possibly their eyes is unclear.

“We also do not know if viral particles can be aerosolized from water or suspended into air after settling and remain infective. While such routes can occur for other coronaviruses, the European Centre for Disease Prevention and Control states that there is currently no evidence to support airborne transmission of the novel Coronavirus. A precautionary approach should be taken until studies eliminate other routes of transmission.

“Epidemiological studies also suggest that transmission rates of COVID-19 currently might be higher than those of SARS and MERS. Scientists have estimated that each person with the new Coronavirus could infect somewhere between 1.5 and 3.5 people without effective containment measures, according to [the paper] ‘Early Transmissibility Assessment of a Novel Coronavirus in Wuhan, China‘ [the source of the outbreak] in the Elsevier SSRN (Social Science Research Network).

Helix Water District, serving San Diego’s east county communities, is among operators in the water industry urging caution but also providing reassurances, such as this on its website:

“Coronavirus (COVID-19) is known to spread from person to person through close contact, similar to how the flu is transmitted. There is currently no evidence to support that Coronavirus (COVID-19) is transmitted through drinking water. Coronavirus (COVID-19) can be disinfected through use of ozone, chlorine and other treatment processes used in processing your tap water.”

Swimming World continues to monitor the situation while we await responses and further information from health authorities, including the World Health Organization (WHO), which told us a week ago:

“This is still a new virus and we are still gathering more epidemiological data to understand better the transmission. Based on the current data, we see that COVID-19 is transmitting mainly through respiratory droplets.”

Original article: published February 27, 2020

Research conducted at the University of Arizona more than 12 years ago has raised questions about whether the new coronavirus COVID-19 strain behind a global health emergency could be transferrable through water in the way that stomach ‘flu and other more common viruses are.

In Germany, a 47-year-old man is being cared for in isolation after testing positive for the virus during a four-day visit to a giant sub-tropical pools complex south of Berlin. The pool, with more than 1,000 visitors a day, remains open as its 91 staff undergo tests.

The new coronavirus is still being broken down by scientists to determine its nature and what might kill it off. However, previous coronavirus strains, research dating back to 2008 appear to show, have thrived in waters between 4C and 23C. It dies more rapidly in wastewater, researchers found.

Research by Patricia M Gundy, Principal Research Specialist, and Charles Gerba, Professor of epidemiology and bio-statistics in the Environmental Science Department at The University of Arizona in 2008 is summed up in the following abstract:

“The advent of severe acute respiratory syndrome and its potential environmental transmission indicates the need for more information on the survival of coronavirus in water and wastewater. The survival of representative coronaviruses, feline infectious peritonitis virus, and human coronavirus 229E was determined in filtered and unfiltered tap water (4 and 23°C) and wastewater (23°C). This was compared to poliovirus 1 under the same test conditions. Inactivation of coronaviruses in the test water was highly dependent on temperature, level of organic matter, and presence of antagonistic bacteria. The time required for the virus titer to decrease 99.9% (T99.9) shows that in tap water, coronaviruses are inactivated faster in water at 23°C (10days) than in water at 4°C (>100days). Coronaviruses die off rapidly in wastewater, with T99.9 values of between 2 and 4days. Poliovirus survived longer than coronaviruses in all test waters, except the 4°C tap water.”

The paper can be read in full by subscribers at Researchgate. We have reached out to the researchers for deeper understanding.

It is unclear whether the new virus can survive in water, what kind of water, what temperature of water, treated water and so forth. The answers may be critical to aquatic sports and others working in water environments.

Swimming World has asked several leading public health institutions, including the CDC in the United States, for guidance on the relationship between the virus and water. The responses focus on the novel nature of the current coronavirus and the infancy of the research process.

A spokesman for the Work Health Organisation told Swimming World:

“This is still a new virus and we are still gathering more epidemiological data to understand better the transmission. Based on the current data, we see that COVID-19 is transmitting mainly through respiratory droplets.”

Germany’s Public Health body, the Robert Koch Institute, is in charge of providing information on disinfectants/procedures in medical settings only. AS such it has no data related to the significance of the relationship between water and the coronavirus.

In general, however, a spokesperson for the Institute made the following point:

“Many features of SARS-CoV-2 are still not clear and need to be further investigated – it has been only 2 months since this virus has shown up, I’m not sure if anyone has addressed this question of pools yet in further depth.”

Swimming World will bring you more answers as and when we get them on that aspect of the virus.

Meanwhile, a real-life test case may be underway:

Giant German Pools Complex Suffers One Positive Test – But it’s Business As Usual


Tropical Islands – the outdoor zone – Photo Courtesy: Craig Lord

Attention turns to whether water – including tap water, pool water and open water, could play any significant part in the spread of the new coronavirus just as Germany contemplates the potential consequences of a single positive test returned by a man who went swimming at the giant, domed Tropical Islands leisure swimming pool complex south of Berlin.

On an average day, the vast complex hosts thousands of swimmers, including many tourists and travellers from further afield, inside and beyond Germany.

The man who now has the virus visited Tropical Islands with his family of five – and stayed for four days. The complex, with sub-tropical gardens, exotic birdlife, including flamingos, a large sauna and steam-room complex, restaurants and entertainment shows, has cabins and tents for hire for those who wish to stay overnight.

According to the Brandenburg Ministry of Health, the 47-year-old man from North Rhine-Westphalia is being cared for at the University Hospital in Düsseldorf. He left behind a deal of fear.

Today, 91 employees of the pool were tested for the virus, yet the complex remained open and was packed.


Tropical Islands in Germany – Photo Courtesy: Craig Lord

“Our previous tests have shown that there was no increased risk of infection,” said the responsible health authority in Dahme-Spreewald. “The risk of infection is almost zero.”

Kim Schäfer, Marketing Manager Tropical Islands, told the spa news agency: “Between February 20 to 23, we had between 3500-4000 guests per day because we were on vacation in Saxony. The people who worked on those days were still on duty when we got the news. Until the test result they are now free. With 1.2 million guests a year, we are one of the largest tourism organizations in Germany. The health authorities have been here all day, have examined our measures and evaluated that there is no danger for the visitors. Therefore we have remained open.”

Brandenburg’s Minister of Health Ursula Nonnemacher told media that the infected man had had no very close contacts with other bathers and that the authorities knew precisely who he had been in close contact with.

Other visitors have been told they need not but can submit themselves for testing if they wish. There has been no mention made of whether the environment at the complex and the many levels and temperatures of waters therein are significant or not.

Hungarian Pool Closure

In Hungary, the Bitskey Aladár swimming pool in Eger, in the north of the country,  has been for an indefinite period as a precautionary measure after the local waterpolo team played a Champions League match in virus-hit Brescia, in northern Italy, last weekend.

Eger Mayor Ádám Mirkóczki told a press conference that he had taken the decision to close the pool following reports of coronavirus cases in northern Italy. He had asked the interior ministry for instructions for advice and they issued an instruction last Monday that the players and staff members returning from Brescia should not be allowed to use the swimming pool until further notice.

However, the health authority ÁNTSZ informed the club on Tuesday afternoon that the pool was open again, just to the players, for training and upcoming games, Mirkóczki added before saying he was “appalled” that the players had not been tested for the virus.



  1. avatar
    Rebecca Klatch

    I am an avid swimmer. But at age 67 I am now hesitant to swim in a public pool due to possible infection with coronavirus.
    Please send me all updates about swimming and coronavirus. Thank you very much.

    • avatar
      Annie Edwards

      I am a 71 year old who does aqua fit every day…how do l know if l am safe?

    • avatar

      I swim 3-4 x a day Should I be concerned about contracting the corona virus ?

  2. avatar
    Ernest Valencia

    I am an avid swimmer as well
    62 years of age please let me know

    • avatar
      Mustapha elahmadi

      Can corona virus survive in a tap water?
      Thank you.

  3. avatar
    Sandy Rubin

    77 year old husband swimming —— Coronavirus case has occurred in our town. Would love to know if he should stop.

  4. avatar
    Cherrie Chilom

    Triathlete swimmer in San Diego with many cases.
    Would appreciate updates.
    Thank you.

  5. avatar
    John Fleming

    I am 72 with one kidney. Is it safe to safe to swim in a public pool?

  6. avatar
    Simone Bonneau

    I am 64 and need to know if I should do water aerobics at my senior center as I wonder if anyone can spread the virus in the small pool. We are all seniors and at a higher risk.

  7. avatar
    Emmanuel Mavromatakis

    I am 75 and practically swim everyday. I try to visit the sports centre early in the morning when it is less busy. I curry a disinfectant which i use as soon as i exit from the sports centre. Please keep me informed as due to spine problems i cannot jog or walk without discomfort.

  8. avatar
    Barbara Thompson

    I am seventy one with an aortic aneurysm. I also want to know if it is safe to swim in a public pool. Also, can I safely swim in a major lake? I live near Lake Michigan. Thank you

    • avatar
      Daniel H

      I doubt you’re swimming in Lake MI right now!

  9. avatar

    Going to lodge with my granddaughter who loves the use of the indoor pool there. What are the risks?

  10. avatar
    Carol Hargreaves

    I am a very keen swimmer and swim 3 times a week I a public pool in my home town . We’re corona virus cases are . Am i dafe to still continue to go . Kind Regards Carol.

    • avatar

      That’s my question too.

  11. avatar
    Annie Edwards

    I am a 71 year old who does aqua fit every day…how do l know if l am safe?

  12. avatar

    Wow! sounds like another pathogen that maybe waterborne. Sadly it will never be addressed or mentioned by politicians or the media in regards to the movement of ballast water by international ships, that are known to disperse bacteria and virus around the world in their ballast water discharges.

    • avatar
      Craig Lord - Swimming World Editor-in-Chief

      Thanks Don. We are still seeking some responses form some experts… I know some of them have much to do right now and questions from swimmers are something of a drop in the ocean to them but there is a distinct silence when it comes to providing a clear answer on water/CV relationship … there appears to be little to no risk in treated pool water, according to some industry experts (we could not say, of course) – and wastewater, treated. appears to kill off CV fairly quickly… but far less certain are the v few replies, when it comes to open water… and general comments about how CV might be transmitted by water…

  13. avatar

    Let us trust God to guide our behavior as we endure this trial. Eventually it will pass.

    Meanwhile, the ACTS prayer model would appear to be in order:
    Thanksgiving then
    Supplication (our specific requests for divine assistance)

    I am 70 and and in very good health. Based on what I read this morning at this site, I am suspending my distance swimming (2 miles per week) and weekly lessons, until more facts are known.

    Thank you, Swimming World, for your fact-based coverage when so many of us need it!

    • avatar
      Craig Lord - Swimming World Editor-in-Chief

      Thanks Eugene and answering your other note too…

  14. avatar

    From the U. Arizona 2008 research (above):
    “Inactivation of coronaviruses in the test water was highly dependent on temperature, level of organic matter, and presence of antagonistic bacteria. The time required for the virus titer to decrease 99.9% (T99.9) shows that in tap water, coronaviruses are inactivated faster in water at 23°C (10days) than in water at 4°C (>100days).”

    In Fahrenheit, 23°C is 73.4°F. Swimming pool water temperatures are usually 80-83°F, and CV inactivates at higher temperatures. T99.9 at 73.4°F (23°C) is 10 days. From the article, we don’t know T99.9 in the range of 80-83°F. Perhaps the original research has more than two data points (39.2°F and 73.4°F), and could be extrapolated +6.6°F (to 80°F) and +9.6°F (to 83°F) if the shape of the curve is known by the U. Arizona researchers. This would appear to be a reasonable inquiry for Swimming World to pose to the researchers, and it would not require any new bench research.

    10 days at 73.4°F concerns me. If T99.9 at 80°F is predicted to be 5 days (as a result of a reasonable extrapolation), then CV from an asymptomatic infected swimmer can pass from the swimmer into the pool and possibly infect another swimmer for 5 days, despite the chlorination of the pool water.

    Since pool water contact with eyes, nose, and mouth is unavoidable when swimming, it would appear that we put ourselves at risk by swimming, until a CV vaccine is included in our annual flu shot.

    • avatar
      Craig Lord - Swimming World Editor-in-Chief

      Eugene, many thanks for your comment and knowledge. I will pursue it with the researchers – and hope they have time to reply…
      Much appreciated.

      • avatar

        Tap water would have much less chlorine than Pools to .. at least 10 times less.. Pools in Australia average 3pp for Chlorine. Tap water is .1pp

  15. avatar
    Kathy Hyatt

    I am also a swimmer in a public YMCA inside pool. Please keep us updated in this virus and the pool. Thank you.

  16. avatar
    Catherine Milton

    I am a 72 year old avid swimmer and have decided pause until an update on risks.

    • avatar
      Craig Lord - Swimming World Editor-in-Chief

      Sorry to hear that you and others are having to take a precaution away from the pool. We’re seeking answers, Catherine, and will bring you answers as we get them.

  17. avatar
    Catherine Milton

    Thank you!

  18. avatar

    Keep me posted. I swim and teach and coach. Thanks!

    • avatar
      Craig Lord - Swimming World Editor-in-Chief

      We will do Nancy… and all seeking information… we’re seeking answers for you…

  19. avatar

    Isn’t there already data that shows the virus cannot last in higher air temperatures so would that apply to hire water temperatures as well?

  20. avatar

    Will the covid-19 virus survive in a steam room?

  21. avatar
    Cheryl Koeller

    I teach swim lessons to all ages, including a 68 year old. I am 60 myself. Our pool is kept at 84. Should I be concerned? I don’t want to get sick or have my swimmers get sick. Thank you.

  22. avatar


    You may want to wait a week or two before conducting swim lessons, until Craig Lord gets a response from his questions to the U. Arizona researchers. Their experimental results with tap water at 73.4 degrees Fahrenheit suggest that coronavirus can live for up to 10 days. Your pool is 10.6 degrees higher, which should lower the coronavirus lifetime. However, pool water typically has 1 to 3 ppm of chlorine, whereas tap water has 4 ppm (EPA standard). So the disinfecting power of pool water is significantly less (33% to 300%) than tap water at the same temperature.
    It would appear that the chlorine in pool water does not kill coronavirus on contact. Rather, it would appear to linger in an active state for on the order of 10 days, so other swimmers could be infected by it.

  23. avatar
    Jan Friedmann

    Hello > I work as well in a pool for teaching small children and infants. We currently have 300 students per week. We keep our pool at 89 degrees. Can you please email us when you get the results from the U.Arizona researchers as per the above information.
    Att: Jan
    Aquatic Director.

  24. avatar
    Rafael Arechiga


    Hello, I will be going with my family to a Private Resort with swimming pool, and I will like to know the risk of swimming, thank you

  25. avatar
    Dai Mingeri

    Doesn’t the CV need sufficient quantity to be infecting?

    A typical pool of 6 lanes (about 15 ft wide) and 25 yards (75 ft long) length, assuming uniform 4 ft depth, holds 13,500 cubic feet, or more than a hundred thousand gallons of water (100,987 Gal).

    How many coronaviruses does that amount of water contain for it to be contageous, assuming they distribute evenly?

    • avatar
      Craig Lord - Swimming World Editor-in-Chief

      I don’t think it’s being suggested that the body of a pool would be the problem… it is the proximity of people in an environment where the element could assist transmission.

    • avatar


      It is my understanding that a single coronavirus breaching the cell membrane in eye, nose, or mouth tissue can cause an infection. A virus requires a host organism (e.g. a human) to survive and replicate itself.

      According to the CDC, when SARS-CoV-2 infects a human, the human may be asymptomatic for 5 to 7 days before spiking a fever, developing a dry cough, becoming fatigued, etc. During the asymptomatic period, I believe the initial coronavirus replicates itself.

      So it would appear that the minimum number of coronaviruses which cause a person to be infected is one. While the density of SARS-CoV-2 in an Olympic pool may be low, if it only takes one coronavirus to start the infection, should we put ourselves and our loved ones at risk? Or should we wait for the researchers to perform more experiments?

      Best regards for your good health!

      • avatar
        Craig Lord - Swimming World Editor-in-Chief

        Thank you Eugene.

  26. avatar
    Maria dillon-remy

    I swim in the ocean in the Caribbean- is it safe?

  27. avatar
    Bianca Chulis

    May there be a few things the AZ study fails to mention possibly as well as the CDC? What are your thoughts on these aspects of concern? If you live in a Condominium complex considered by law to be semi-private not fully public and the code requires “all pool staff” that are maintaining the pool and are around it in any way to be officially and legally licensed and certified by the authorized listed agency as well as post their certifications by the pool for residents view. The most minimal requirements by law require once daily chlorine, bromine and pH balance checks with potential for twice daily checks depending where you’re located. Regardless, all pool certified staff are to have ability to check pool frequently and at all times keep it free and clear of debris; disinfect all surrounding pool surfaces, entrances, gated entrances, chairs, lounge chairs, tables, floats and or noodles, flooring, cement, concrete, railings, etc at all times the pool is open for operation. The certified pool staff must also have full authority to close the pool immediately if the water chemicals are out of balance and they need to balance. Based on the sun, shade, heat or cool weather temperature may cause frequent variations and problems in hotter areas such as the Western USA or tropical areas. My concern is for a Condominium complex of seniors near the University of Arizona, coincidentally, which does not certify all pool staff nor does the pool staff remain at the pool. The pool staffbl is comprised of its general maintenance staff that check the pH of the pool sometimes daily or perhaps once a week. No areas or items around or near the pool even during this time of Pandemic are disinfected. Yet, residents, senior aged continue during the Pandemic to flock to the pool and remain within 6 feet or closer of each other enjoying the cool water, exercising, socializing. Clearly they are bored, unable to determime what and how to fill their time within their own Condo wall boundaries alone. Instead, they eagerly willing seek group activities and even try to create them almost to risk their and other residents health without a concern for others well being. Additionally, the Management Association and Board continues to support the Residents usage of the pool especially as well as other group activities. The complex neither meets State or County Staff Pool Certification requirements nor water chemical testing requirements daily nor make any effort to clean or disinfect the areas, entries, furniture, railings, flooring, equipment in or around the pool area at all nor try to eliminate or prevent Coronavirus. In your opinion, would you recommend that this pool be closed until the Coronavirus Pandemic has passed for the residents own protection? Would you feel safe swimming in this pool based on this information? Thank you for your help! Perhaps, University of Arizona will also consider these subjective factors in the future when making suggestions as it appears certain age groups, more private pools and power center controlled Boards and Management groups have goals other than health and safety potentially which are the bottom dollar and keeping snowbirds happy rather than free from the Coronavirus.

    • avatar
      Craig Lord - Swimming World Editor-in-Chief

      Bianca, we’re not an authority on safe levels of chlorination in pools and related subjects and their relevance to safety, neither in general nor in Corona season. We have been bringing and will continue to bring relevant official advice to the attention of readers. We will publish updated advice on home pools and hot tubs and the like this weekend. We cannot answer your question beyond this: in the circumstances and given the relatively low level of specific advice from scientists and official bodies when it comes to the safety of swimming in a variety of conditions and circumstances right now, I would ‘feel safe’ in situations where I had specific knowledge of the environment I was contemplating entering into and had control over the circumstances and measures of that environment. Anything less than that and you enter into the realms of personal risk and any agreements you may have between yourself and those legally responsible for the environment in your scenario. As stated, we’re updating the guidance soon and you will be able to access that through our online pages.

      • avatar

        Thank you Craig Lord. I feel, that may be as perfect a response as possible. Additionally, each individual must follow their conscience to do what they would feel would puts everyone at least risk. I appreciate your concern, knowledge and ability to listen to each person’s question and consider and address it accordingly and appropriately. I feel it makes this a valuable resource. Thank you Craig Lord.

  28. avatar
    Bianca Chulis

    Thank you Craig Lord. I feel, that may be as perfect a response as possible. Individuals must follow their conscience to do what they feel puts everyone at least risk. I appreciate your concern, knowledge and ability to listen to each person’s question; consider and respond appropriately. You continue to be a valued and respected resource. Thank you Craig Lord.

  29. avatar

    When will you post information related to private home swimming pools

  30. avatar

    Please update this important thread. I do not believe the CDC.
    “Coronavirus survival in pool water for up to 10 days” combined with “no vaccine possible” means no less than giving up my fishlike swimming and wearing my new speedos for Tai Chi instead…