The Centers for Disease Control and Prevention (CDC) recommends washing your hands often, for at least 20 seconds at a time. When rubbing soap on your hands, be sure to lather the backs of your hands, between the fingers, and under your nails.

Don’t worry about getting the water very hot. According to a study published in the International Journal of Consumer Studies in January 2013, most people believe using hot water is more effective than washing with warm, room temperature, or cold water. But there’s no evidence to support this. Heat does kill bacteria, but at a much higher temperature than is comfortable for washing your hands.

“There is no one best water temperature to wash one’s hands,” says Dr. Grief. “If your hands are really dirty and greasy, use of warm to hot water will do a better job of trapping dirt and grease within the soap, allowing for a more thorough cleaning.”

The type of soap also doesn’t typically matter, according to Grief, “as long as it lathers and spreads over the hands sufficiently to trap the germs.”

Hand Sanitizers: What You Need to Know

Alcohol-based hand sanitizers make a good substitute for handwashing when soap and water are not available.

According to the CDC, sanitizers with an alcohol concentration between 60 percent and 95 percent are more effective at killing germs than those with a lower alcohol concentration or non-alcohol-based sanitizers.

The right way to use a sanitizer is to apply it to the palm of one hand and rub it all over the surfaces of both hands until they’re dry. Even though alcohol-based hand sanitizers can deactivate many types of microbes when used correctly, they’re not effective if people don’t use enough sanitizer or wipe it off before it dries.

The CDC points out that soap and water are more effective than hand sanitizers at removing or inactivating certain kinds of germs like norovirus, which is the most common cause of gastroenteritis.

When Should You Wash Your Hands?

Regular handwashing is especially important at certain times. Always remember to wash up:

  • Before and after preparing or handling food
  • Before eating
  • After changing diapers
  • After using the bathroom
  • After sneezing, coughing, or blowing your nose
  • After touching an animal or animal waste
  • After handling garbage
  • Before and after treating a wound
  • Before and after caring for a sick person

Additional reporting by Linda Melone.