How to

5 June 2017

Does Water Temperature when Washing Hands Affect Cleanliness?


It has long been advised that in order to remove as many germs as possible when washing your hands, you should make sure to use hot, or at least warm, water. However, a recent study seems to suggest that there is in fact little truth behind this assertion, and that cold water is arguably just as good as warm.

The study, conducted by scientists at Rutgers University-New Brunswick and published in the Journal of Food Protection, asked 20 participants to wash their hands 20 times with water at temperatures of 15°C (59°F), 26°C (79°F), or 38°C (100°F). The volunteers also experimented with varying amounts of soap.

Before testing commenced, participants had a covering of harmless bugs applied to their hands in order to test how much remained after washing.

The researchers state that the study showed no difference in the amount of bugs present after washing regardless of the water temperature or the amount of soap used, pouring cold water on the classic old wives’ tale.

Research team member Prof Donald Schaffner said, “People need to feel comfortable when they are washing their hands but as far as effectiveness [goes], this study shows us that the temperature of the water used did not matter.”

However, those behind the research do acknowledge that due to the relatively small scale of their study, more extensive research and insight is required concerning how to best remove harmful bacteria.

The results of the study directly contradict advice given within the food industry in the US, where the use of hot water for hand washing is recommended. It does however line up with current NHS advice.

The report went on the assert that is guidelines were to change in line with this new research, heating and electricity bills could be substantially reduced, particularly in the case of restaurants.


Sam Bonson

Sam is an aspiring novelist with a passion for fantasy and crime thrillers. He is currently working as a content writer, journalist & editor in an attempt to expand his horizons.