The claim, drinking water can cure Covid-19 is very misleading. Yes, drinking water can help the immune system function and relieve illness, it is not the reason someone gets over the virus. Water does not kill the virus.
According to BBC, Kalpana Sabapathy, a clinical epidemiologist at the London School of Hygiene and Tropical Medicine explains, "infections often begin after we’ve been exposed to thousands or millions of viral particles, so sweeping a few down the oesophagus is unlikely to have much of an impact. “One gaping hole in it is the likelihood that you managed to flush all of them down into your stomach,” she says. “You would probably have already got them in your nostrils by then, for example – it’s not fool proof,” she says. And here lies another of the main flaws in the idea. Even if the virus hasn’t already managed to find its way inside the cells of your respiratory tract, it can also get into the body in other ways. While some people might become infected by touching their mouth with contaminated fingers, it can also enter the body by touching the nose or eyes." Kalpana Sabapathy argument reveals how drinking water will not be affective because the virus can access the body through the eyes or nostrils as well. Water will not be affective and even if the infection accessed through the mouth, water will have little to no impact.
https://www.bbc.com/future/article/20200319-covid-19-will-drinking-water-keep-you-safe-from-coronavirus
In addition, ABC News debunks the myth that water gets rid of the virus, this article states, "There is no current scientific evidence behind the claim that keeping your mouth moist will prevent infection with coronavirus. But staying hydrated can help keep your immune system strong." "The temperature of the water you drink is not important, however, drinking water and staying hydrated is important for many reasons. According to the Centers for Disease Control and Prevention, water helps your body with a number of functions, including regulating body temperature."
Dr. Simone Wildes, an infectious disease specialist at South Shore Hospital in Boston agrees: "Hydration is always good; it helps with all bodily functions."
"People can usually meet their fluid needs by drinking water when they are feeling thirsty and drinking with meals. Your body requires more water when you are running a fever, are more physically active or have diarrhea or vomiting." This article states how water itself will not kill the virus, but drinking lots of water to stay hydrated will help your immune system fight off the virus.
https://abcnews.com/Health/debunking-myths-avoid-cure-coronavirus/story?id=69578209
To counter those points above, AP News suggests, "False. Drinking water prevents dehydration, but it will not prevent anyone from catching the new coronavirus." "THE FACTS: Doctors caution against believing homegrown advice that social media users are spreading online as ways of preventing the virus. Dr. William Schaffner, an infectious disease expert at Vanderbilt University, said while medical professionals typically recommend keeping up fluid intake when sick, drinking more water will not keep anyone from catching the virus."
“We always caution anyone healthy and people who are sick to keep up fluid intake and keep mucus membranes moist,” he said. “It makes you feel better, there is no clear indication that it directly protects you against complications.” Dr. William Schaffner clearly states how drinking water will not prevent someone from getting the virus, but it can help fight off the virus and "keeps the mucus membranes moist." He claims that like any other illness that fluid intake is important for fighting a virus, but does not kill a virus.
https://apnews.com/article/8551030197
In addition, a fact or fiction article from the The World Health Organization claims, "There is no evidence that drinking lots of water flushes out the new coronavirus.However, for good health in general, it is recommended that people should have 8 glasses of water every day." The world health organization reveals how drinking water does not flush out coronavirus, but for overall health, drinking 8 glasses of water can keep someone healthy. Staying healthy can prevent the coronavirus or lessen the effects of the virus, but water cannot get rid of the virus.
https://www.who.int/southeastasia/outbreaks-and-emergencies/covid-19/What-can-we-do-to-keep-safe/fact-or-fiction
To conclude, an article from Universitas Gadjah Mada, reveals, "Internal Medicine Expert (Intern Pulmonologist) FKKMK UGM, dr. Sumardi, Sp.PD, KP., FINASIM., firmly denied claims of drinking hot water, and taking a hot shower could kill Covid-19." He explained that hot water, whether consumed or for bathing, would not be able to reach or kill the virus because the Covid-19 virus is ensconced in the body’s cells. Meanwhile, the body will automatically regulate its temperature when getting a virus attack."
“If a virus enters the body, the body temperature will rise by itself to neutralize the virus. So, there is no need to drink or take a hot shower because it will disrupt the body system,” Sumardi explained." Even though this article talks about hot water, Dr. Sumardi claims that water will not kill the virus no matter what temperature. The body will just adapt to neutralize the virus. If anything, drinking hot water can cause more harm than good because it will disrupt the bodies natural function of getting the virus out.
https://ugm.ac.id/en/news/19427-ugm-expert-hot-water-cannot-eradicate-covid-19-within-the-body-s-cells/