The study, published in the Journal of Environmental Health, indicates a third of the people involved in the study didn't use soap and 10 percent didn't wash their hands at all.
Linda Dickey, director of infection control for the University of California, Irvine Medical Center, said keeping hands clean is one of the most important steps for avoiding sickness and spreading germs to others.
It takes 15 to 20 seconds of vigorous hand-washing to effectively kill germs, the Center for Disease Control and Prevention found. However, the study found people only washing their hands about 6 seconds, on average.
Clean hands can stop germs from spreading from one person to another and throughout an entire community, the CDC said.
To avoid the spreading of germs, Dickey said to:
-- Clean under nails at least once a day.
-- Keep hands away from the face.
-- Sneeze or cough into the crook of your arm.
-- After washing your hands, use a towel to turn off the faucet and open the door, if possible.
The CDC's step-by-step guide on the correct way to wash hands says to:
-- Wet hands with clean, running water -- warm or cold -- and apply soap.
-- Rub hands together to make a lather and scrub them well; be sure to scrub the backs of your hands, between your fingers, and under nails.
-- Continue rubbing your hands for at least 20 seconds. Need a timer? Hum the "Happy Birthday" song from beginning to end twice.
-- Rinse your hands well under running water.
-- Dry your hands using a clean towel or paper towel.