Does Hot Water Make A Difference?

Washing your hands is something that everybody does. Whether it is before eating or after going the bathroom – we all wash our hands sometime in the day. When its cold out we tend to wash our hands in the warm water, but when its a warm day, we tend to refresh ourselves by washing our hands in cold water. However, should we be washing in just one temperature. Is it possible that one temperature is more beneficial than another temperature for eliminating all bacteria on ones hand?



According to DebGroup, a study was conducted in order to determine if the temperature, being hot water, had any effect on ridding pathogens on one’s hand. In this study, the Null Hypothesis would be that hot water as effective as cold water when washing hands, while the Alternative Hypothesis would be hot water is more effective than cold water when washing. The study surveyed a total of 510 adults and were asked a series of questions regarding how they wash their hands; for example, how often they wash, how they wash, how long they wash for etc. According to National Geographic, 70% of the people surveyed believed that washing their hands in warmer water was more beneficial. By the end of the study it was determined that the hot water had no effect on the amount of pathogens left on the skin compared to cold water. Another study, according to the New York Times, conveyed by scientists from the Joint Bank Group/ Fund Health Services  had participants contaminate their hands. The participants washed their hands for 25 seconds in soap and water ranging from 40 degrees Fahrenheit to 120 degrees Fahrenheit. It was then observed to see if the hands washed in the hotter water had less bacteria than the hands washed in cooler water. The study determined that the temperature had no effect on the outcome of the bacteria on the hands. Hot water is as effective as cold water when washing hands. This would mean that the Null Hypothesis is true. It is true that heat does indeed kill off bacteria, so why would it not be the same for hot imageswater? According to Amanda R. Carrico from Vanderbilt University, she confirms that heat does kill off bacteria. However, she explains that in order to acquire that amount of heat in your water, it would be very unsafe for humans to wash with. That amount of heat would burn and cause great discomfort which all in all, is unnecessary in order to wash your hands. So, as long as you wash your hands with soap and water for the normal amount of 25 seconds, you’ll have clean hands despite the temperature of the water.



Altogether, it does not matter what temperature water you use to wash your hands. Washing your hands is definitely a vital part of everyday living, so as long as you use soap and water, you’ll definitely be clear of any possible bacteria and pathogens lying on your hands. So, make sure you wash your hands, but it won’t matter what water temperature you use!

Work Cited



9 thoughts on “Does Hot Water Make A Difference?

  1. Charles Hart

    Wow, I was shocked that 70% of the people surveyed said washing in warmer water was better for them and they are wrong. I’ve said this on other blogs, but it really is amazing how confirmation bias affects us. We choose to believe what we believe is right, and if anything else is different than our hypothesis, we deny it, try to find a way to disprove it by any means necessary, or we forget it entirely. You have two studies to back up your hypothesis. While this is by no means concrete, it does show that you may be on to something. Once more and more studies find your hypothesis to be true, I think we can prove that temperature does not matter when washing your hands. I do find it interesting that NY Gov ( says wash your hands as warm as possible, contradicting your hypothesis. They should certainly do more studies to find out a definitive answer.

  2. Luyi Yao

    From my previous views, I thought that we just use water to wash bacteria away from our hands. Also, i didn’t think the hottest water that people can commonly suffer is not enough hot to kill bacteria. Actually, the fact is just what I think. However, soap is very effective. I just know that we should wash hands with soap and water for at least 25 seconds. I usually wash my hands quickly… This tip is useful! Lastly, this post is very logical and easily understanding. I like your topic!

  3. ljj126

    This is so great! all my life my father would always tell me to use as hot as water as I could to wash my hands. I did it but not because I wanted to because it was in fact painful. So the null hypo was in fact true! this means you can wash your hands with hot or cold water. I was also told that when washing dishes you should wash in hot water and rinse in cold water. this of course is just and anecdote or old wives tale but some of it does makes sense as shown in this article
    So it goes without saying that there is a certain element that hot water can matter however, it is highly unlikely for people to wash their hands that tends to cause them discomfort and pain.
    great Blog!

  4. Mairead Donnard

    This was such an interesting blog to read! I have always assumed that washing my hands with warmer water was in turn more beneficial in killing the bacteria on my hands than cold water. Your inclusion of Amanda R. Carracio’s comment further explaining how the temperature of the water does not really impact the clean was extremely beneficial in furthering your point. With this being said, this blog definitely made me think of the hand towel that we use after washing our hands. Here is an article that you might find interesting:
    The article talks about the dangers of using the hand towel given that towels actually contain a lot of germs. All that effort to make sure your hands are bacteria-free and then using a hand towel (aka Germ bomb) is ironic!

  5. tmv5147

    I have always wondered about this from time to time while washing by hands. Especially now in college with all the germs, people and things we touch throughout the day. I hate being sick, I’m not a “germophobe” but I do find myself thinking about the germs on somethings throughout the day. I have heard in the past about in the past but I have always felt more satisfied washing my hands with warmer water. Although this study seems accurate with a large group of people who were closely observed with contaminated hands, it doesn’t show how they were contaminated. There are different types of bacteria so it would be more realistic to divide the field of people into groups and have them go out for an hour or so and have them take a list of things to come in contact with and then compare the results. Maybe it takes a certain type of temperature to get rid of certain bacteria’s. Another factor that could have been talked about in the studies are which type of soap the participants used, weather they did or didn’t use any at all. Third variables such as hand sanitizer is also a discussion that could have been implanted in this study, instead of having a group wash their hands after touching the list of things they could use hand sanitizer and then compare the results to those who washed their hands with the water.

  6. Daniel J Lehecka

    Going with what Kateryna said, I think it’s interesting that we’re so willing to listen to people just because they’re adults. There’s not much reason to believe that an elementary school teacher really has an understanding of this subject, so I don’t understand why we’re taught to take their word as law. I think this is similar to the idea that being in cold weather will make you sick, which a lot of older people still preach but hasn’t really been proven completely true. This article ( talks about a study that shows a potential link, but as we know that’s not a guaranteed cause.

  7. Nicholas E Schneider

    Honestly, I’ve never wondered much about whether or not the temperature of the water a person washes their hands with has an effect on the cleanliness of their hands. With this being said, (unless it was a hot summer day like you mentioned) I’ve always washed my hands with soap and very warm water and felt like doing so gets my hands cleaner than washing with cold water would. Perhaps, like Kateryna proposed in her comment, this is because adults/superiors have always preached washing “for at least 30 seconds with warm water!” Maybe my preconceived notion developed because I typically associate the warm water from a hot shower with getting clean, either way, it’s interesting to learn after all this time that washing your hands (and presumably your entire body) with cold water is just as effective as washing with hot water. Hopefully my family members can keep this in mind before they leave me with no hot water to shower with.

  8. Olivia Anne Browne

    Really good post! I never even really thought about which temperature mattered. I always tend to wash my hands with warm better because it feels better. I am delighted to know that it doesn’t really make a difference what temperature you wash them at. Good job including in class concepts in your blog. What is interesting to me, is that you would think one temperature is superior to another but the question would be which one and why. I feel as though one would definitely find evidence to prove this right.
    Great job!
    Check out this article on how washing hands saves lives.

  9. Kateryna Okhrimchuk

    I was just thinking about this when my little sister came home from school during break! I remember when I was in elementary school, all the teachers would always tell us to wash our hands with warm water instead of cold because the water water “killed more germs”. I never really gave it a second thought and just blindly followed this for most of my life. Sadly, I feel like this appeal to authority happens a lot of the time when dealing with science. We see someone who is older or has more experience or a higher degree and trust their opinion over your own, even if you had the right idea all along. I think its really interesting how a lot of scientific breakthroughs happen when people disagree with each other and stick to what they believe/know, not letting people put down their discoveries just because another idea has been accepted for a very long time. It’s nice to know that we don’t have to deal with washing our hands with warm water during the summer anymore and that cold water does the job just as well!

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