Cold or Hot: Which One is Right and Which One is Not

For years we have been instructed that, in order to properly kill bacteria, we should wash our hands for around thirty seconds with warm to hot water, and soap. As children we were told that this was the only way to avoid getting sick and spreading bacteria. As we grew older and discovered hand-sanitizer, we were once again told that washing our hands with warm water and soap was the best way to truly kill germs. But what’s the deal with warm water? Do we always have to wash with warm water, or will cold suffice? This is a question that I have always wondered, and it has in turn prompted me to research the subject.

After doing some research, I have found studies that back the theory of using hot water, as well as studies that back up the theory of using cold water. However, there is more overwhelming research that suggests that water temperature does not matter altogether. For example, research professor, Amanda Carrico, who works for Vanderbilt University, conducted a study in which she attempted to prove that the temperature of water does not matter when washing your hands. What she found, according to a post written by Brian Howard, for, was that the hot water we are accustomed to using to wash our hands is actually not hot enough to kill the germs that we think we are killing. For instance, Carrico suggested that the ideal water temperature to kill certain types of germs would need to be upwards of two-hundred degrees Fahrenheit.

Another tidbit of information that helps to back up the theory that water temperature doesn’t matter is the fact that, on their website,, the Center for Disease Control doesn’t even mention that there is an ideal water temperature to wash your hands with. On the page in which the CDC describes the appropriate procedure for washing hands, which you can find here, there is no mention of a specific temperature that is suggested to help rid your hands of bacteria and germs. Instead, the CDC simply relays the message that we have all heard for years: make sure to wash your hands thoroughly with antibacterial soap and water.

In the end, it is your choice whether or not you choose to wash with warm or cold water, but next time you’re at the sink, don’t fret if you can’t get the warm water nozzle to work, because ultimately, it seems like washing with hotter water doesn’t matter after all.




Sources: Handwashing: Clean Hands Save Lives. (2016). Retrieved September 15, 2016, from

Howard, B. C. (n.d.). Washing Hands in Hot Water Wastes Energy, Study Says. Retrieved September 15, 2016, from

Picture: Handwashing: Clean Hands Save Lives. (2016). Retrieved September 15, 2016, from

2 thoughts on “Cold or Hot: Which One is Right and Which One is Not

  1. Olivia Helen Dearment

    This is an interesting choice of topic because I have often thought about this debate as well. I sometimes wonder if hot water really does increase the cleanliness of your hands, but then again I could never decide how that would make sense. This post really cleared that notion up for me. Realistically, the level of hotness that it would take would be too hot for us to handle. I guess also, as long as each individual washes thoroughly with soap, the cleanliness is all the same. I first wondered this because I always felt cleaner with a hot shower than with a colder one, but it seems it was all in my head.

Leave a Reply