Environmental Health & Safety
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Hand Washing Procedures
Does Hot Water Hand Washing Kill More
Germs Than Cold Water Hand Washing?
The short answer is NO, the long answer is:
Soap and warm water have long been said to
prevent the spread of infections, but is warm or hot water really
more effective than cold?
In its medical literature, the Food and Drug
Administration states that hot water comfortable enough for washing
hands is not hot enough to kill bacteria, but is more effective than
cold water because it removes oils from the hand that can harbor
But in a 2005 report in the Journal of
Occupational and Environmental Medicine, scientists with the Joint
Bank Group/Fund Health Services Department pointed out that in
studies which subjects had their hands contaminated, and then were
instructed to wash and rinse with soap for 25 seconds using water
with temperatures ranging from 40 degrees Fahrenheit to 120 degrees,
the various temperatures had "no effect on transient or resident
They found no evidence that hot water had any
benefit, and noted that it might increase the "irritant capacity" of
some soaps, causing contact dermatitis. "Temperature of water used
for hand washing should not be guided by antibacterial effects but
comfort," they wrote, "which is in the tepid to warm temperature
range. The usage of tepid water instead of hot water also has
Wash Your Hands: The Right Way
When washing your hands with soap and water:
Wet your hands with clean running
water and apply soap. Use warm water if it is
Rub hands together to make a
lather and scrub all surfaces.
Continue rubbing hands for 15-20
seconds. Need a timer? Imagine saying "Happy
Birthday" twice through to a friend.
Rinse hands well under running
Dry your hands using a paper
towel or air dryer. If possible, use your paper
towel to turn off the faucet.
Always use soap and water if your
hands are visibly dirty.
If soap and clean water are not available, use an
alcohol-based hand rub to clean your hands. Alcohol-based hands rub
significantly reduce the number of germs on skin and are
When using an alcohol-based hand sanitizer: