Hand Washing 101

Child washing hands.
Washing your hands regularly helps to prevent the spread of infection and illness.
ŠiStockphoto.com/David Hernandez

We've all been there. You and a co-worker exit bathroom stalls at the same time. You -- ever diligent -- wash your hands. Your co-worker, however, smoothes his hair and walks out. He and others like him are the reason why you don't sample candy from the communal jar at the reception desk.

In an observational study in 2007, researchers saw only 77 percent of people wash their hands after using public restrooms. In another survey, only 34 percent of people reported they always washed their hands after coughing or sneezing [source: American Society for Microbiology].


You might be wondering why it's such a big deal, but the truth is that hand washing is one of the best ways to prevent the spread of infection and illness. Not only does it keep germs from affecting you, but it stops any bacteria from getting passed to others and causing illnesses ranging from the common cold to the far more serious -- and sometimes fatal -- Escherichia coli and salmonella.

However, even people who understand the importance of washing theirs hands might not use a technique that's actually effective. Hand washing might seem as simple as rubbing your hands together under the stream of a faucet, but there are several elements to consider, including the how long you should spend washing, how often you should do it, what temperature water you should use and what to do once you're finished.

When you wash your hands, you should have a good idea about safe water temperatures and proper washing techniques. You should also know the best way to dry your hands to ensure you don't re-contaminate yourself after washing. But up next, you'll find out the best ways to prepare for hand washing.


Preparing to Wash Your Hands

You might not have given it much thought, but there are several factors to consider before washing your hands. Perhaps the most important one is to know when you should wash your hands. Mainly, you should wash them after you've come into contact with a large number of bacteria or viruses. For example, you should clean your hands after using the toilet, changing a diaper or handling waste because there are particularly nasty microbes -- including E. coli -- that exist in fecal matter.

You should also wash your hands whenever you're dealing with food, whether that means eating or preparing. In fact, you should wash your hands before and after preparing food, especially when handling raw meat or poultry. Take extra caution whenever dealing directly anything that could contain bacteria, viruses or anything else that could make you or someone else sick. Instances that require hand washing include:


  • After blowing your nose
  • After coughing or sneezing
  • Before and after treating a wound or cut
  • After you come in contact with a sick or injured person [source: Mayo Clinic]

Another important consideration when washing your hands is what type of soap you should use. Normal soap works by having two types of molecular components: hydrophilic (or water-attracting) molecules and hydrophobic (water-repelling) molecules. Once a lather is created, the hydrophobic molecules attach to the dirt and some bacteria on the skin, and they are rinsed away with water. Antibacterial soaps work similarly, except that they kill many types of bacteria instead of just washing them away. However, some scientists have found that antibacterial soaps show no extra benefits to normal soap. In fact, antibacterial soaps might kill only the weaker bacteria on the skin, leaving more powerful strains to breed, which can make bacteria more difficult to eliminate in the future [source: Mayo Clinic]. In any case, you should be using soap every time you wash your hands because it still helps more than water alone.

Now that you know when and with what to wash your hands, read on to learn why soap works better in some water temperatures than others.


Hand Washing Water Temperature

You've probably been told that it's best to wash your hands in hot water because it helps to kill bacteria, but that is actually not the case. Adult skin can begin to scald at 120 degrees Fahrenheit (49 degrees Celsius), but studies have shown that hands washed using water up to that temperature still don't remove bacteria [source: American Burn Association, World Health Organization].

Even though warm water isn't killing any germs, experts commonly recommend it for two reasons. The first and somewhat less scientific reason is that it's usually more comfortable to use than cold water. The second is that many modern soaps are designed to be most effective in warm water [sources: Hand Washing for Life, Christophersen].


Another reason to avoid using hot water is that it can remove natural oils from the skin. This loss of oils can lead to dryness or even cracking of the skin. In some cases, people may even begin washing their hands less to avoid making these symptoms worse [source: Starobin]. In other words, it's important to use water that is warm but not uncomfortable.

It's worth mentioning that modern soaps are still effective at colder temperatures; so, if you don't have access to heated water, it's still better to wash with cold water and soap than with no soap at all [source: Hand Washing for Life].

With the proper water temperature in place, you're ready to move on to methods for washing your hands. Time matters here, so read on to learn a simple method of ticking off the seconds while you suds up.


Hand Washing Methods

Even though you've probably been washing your hands for years, there are quite a few steps that most people either don't know or don't practice. For example, placing your hands under the water before adding soap can help you build up a lather for a better cleansing. Once your hands are lathered up, you should always wash them for at least 20 seconds, or the amount of time it takes you to sing "Happy Birthday" to yourself twice at a regular speed. You should rub your hands together vigorously, though you should be sure to spend some time cleaning your wrists, the backs of your hands, between your fingers and underneath your fingernails. Also, make sure to rinse your hands completely when you're done so that you don't leave a residue.

Once you're finished, it's important to make sure you avoid recontamination before leaving the sink. For example, if possible, use a towel or tissue to turn off the faucet and open the door so you avoid touching areas that typically hold a lot of germs, particularly in public restrooms [source: Centers for Disease Control and Prevention].


Now that your hands are nice and clean, there's still the problem of drying them off. On the next page, read about different ways to safely dry your hands.

Drying Your Hands

Now that your hands have been properly washed, you need to dry them without getting them dirty again in the process.

In many cases, particularly at home, it's difficult to avoid recontamination when drying because you're using the same hand towel repeatedly. This towel can contain the bacteria left in the water on hands from previous uses, and you may be putting them right back on your hands after taking the time to wash them. To properly dry your hands, be sure to either use disposable hand towels or change reusable ones frequently.


Most public restrooms have either disposable towels or hand driers, which blow warm air onto your hands and help to remove any remaining water. Be careful when pressing the button on the drier, since it could be contaminated. When turning it on, be sure to use a different, unexposed part of your body, such as an elbow.

It's amazing how something as simple as good hand washing can help to keep you healthy. Using the tips for when and how to decontaminate your digits should help keep bacteria and other germs at bay. Continue on to the next page for even more information on washing your hands.


Lots More Information

Related HowStuffWorks Articles

  • American Burn Association. "Scald Injury Prevention." (Accessed 9/14/2009)http://www.ameriburn.org/Preven/ScaldInjuryEducator'sGuide.pdf
  • American Society for Microbiology. "2007 Handwashing Survey Fac Sheet." (Accessed 9/14/09)http://www.washup.org/documents/2007ASM-SDAHandwashingSurveyFactSheetFINAL.doc
  • Centers for Disease Control and Prevention. "Wash Your Hands." April 27, 2009. (Accessed 8/24/09) http://www.cdc.gov/Features/HandWashing/
  • Christophersen, Edward R., Ph.D. "Burn Safety: Hot Water Temperature." University of Michigan Health System. Feb. 2, 2009. (Accessed 9/14/2009)https://www.premiercarepeds.com/yourhealth/healthtopics/CRS/CRS/pa_hotwatr_hhg.html
  • Global Hand Washing Day. "Global Handwashing Day." (Accessed 8/24/09)http://globalhandwashing.org/ghw-day
  • Hand Washing for Life. "Handwashing Water: What Temperature?" (Accessed 8/24/09)http://www.handwashingforlife.com/files/HandwashWaterv2.doc
  • Hand Washing for Life. "The 10 Point History of Poor Handwashing." (Accessed 8/24/09) http://www.handwashingforlife.com/the_10_point_history_of_poor_handwashing
  • Kids Health. "Hand Washing." (Accessed 8/24/09) http://kidshealth.org/teen/your_body/skin_stuff/handwashing.html
  • Mayo Clinic. "Hand Washing: An Easy Way to Prevent Infection." Oct. 16, 2007. (Accessed 8/24/09) http://mayoclinic.com/health/hand-washing/HQ00407/NSECTIONGROUP=2
  • Pierce County Health Department. "What Should I Use to Wash My Hands?" Jan. 1, 2003. (Accessed 8/24/09) http://here.doh.wa.gov/materials/what-should-i-use-to-wash-my-hands
  • Starobin, Anna. "Cleanliness Is Next to Effectiveness." (Accessed 8/24/09)http://www.foodquality.com/details/article/820633/Cleanliness_is_Next_to_Effectiveness.html?tzcheck=1
  • WebMD. "Hand Washing: Topic Overview." March 15, 2007. (Accessed 8/24/09) http://www.webmd.com/cold-and-flu/tc/hand-washing-topic-overview
  • WebMD. "Obsessive-Compulsive Disorder (OCD): Topic Overview." June 25, 2008. (Accessed 8/24/09) http://www.webmd.com/anxiety-panic/tc/obsessive-compulsive-disorder-ocd-topic-overview
  • World Health Organization. "WHO Guidelines on Hand Hygiene in Health Care." 2005-2006. (Accessed 9/14/2009)http://www.who.int/patientsafety/information_centre/Last_April_versionHH_Guidelines%5B3%5D.pdf