Here’s where it gets fun—and a little annoying. Just having hot water isn’t enough. You need contact time. Imagine you’re trying to cook a marshmallow. A quick pass over a campfire? Raw. Holding it there for 30 seconds? Golden brown and delicious. Same with germs.
So, if you run a sponge under steaming hot water for two seconds, you’re basically giving the germs a warm hug. You need sustained heat. The CDC recommends water at least 140°F for at least 15 seconds for handwashing, but for dishes, you want to soak them in hot water for a minute or two. And yes, your dishwasher uses water around 140°F to 160°F—that’s why it works so well.
A Word About ‘Germs’ (They’re Not All Bad)
Let’s take a breath. The word “germs” is a catch-all for bacteria, viruses, fungi, and protozoa. Not all of them are evil. In fact, most bacteria are either harmless or helpful. We’re mostly worried about the troublemakers: Salmonella, E. coli, Norovirus, and the like. For those, water at 140°F is great, but boiling is your best insurance policy.
Water heater temperature for killing bacteria/ 140 degrees F
Here’s a fun fact: Some bacteria like heat. There are extremophiles that can survive in boiling volcanic vents. But those are not on your kitchen counter. Unless you live in a volcano. If you do, you have bigger problems than germs.
