Daring Fireball: CDC: Water Temperature Doesn't Matter When Washing Your Hands

CDC: Water Temperature Doesn’t Matter When Washing Your Hands

From the Center for Disease Control’s “Show Me the Science — How to Wash Your Hands”:

Wet your hands with clean, running water (warm or cold), turn off the tap, and apply soap.

Why? Because hands could become recontaminated if placed in a basin of standing water that has been contaminated through previous use, clean running water should be used. However, washing with non-potable water when necessary may still improve health. The temperature of the water does not appear to affect microbe removal; however, warmer water may cause more skin irritation and is more environmentally costly.

Turning off the faucet after wetting hands saves water, and there are few data to prove whether significant numbers of germs are transferred between hands and the faucet.

I’ve always washed my hands with water as hot as I can take it. (Well, that’s not quite true — but when I’ve used cold or cool water because the hot water was taking too long, I’ve felt guilty about it.) It’s just mind-blowing to me that the recipe is just soap and clean water of any temperature.

The CDC’s cited references:

The Environmental Cost of Misinformation: Why the Recommendation to Use Elevated Temperatures for Handwashing Is Problematic.
Hot Water for Handwashing — Where Is the Proof? (I changed the URL for this one to a version where the first page is available to read free of charge.)
Water Temperature as a Factor in Handwashing Efficacy.

★ Saturday, 14 March 2020