Experts in the United States tested 20 people with different water temperatures and they found that hands washed in temperatures of 15 degrees were just as clean as those washed in temperatures of 38 degrees.
Twenty individuals were asked to participate in the handwashing experiments wherein the research team contaminated the participants' hands with harmless bacteria (nonpathogenic E. coli) prior to washing their hands. They were also asked to use 0.5 ml, 1 ml or 2 ml volumes of soap.
Researchers found that warm and cool water remove the same amount of harmful bacteria.
"People need to feel comfortable when they are washing their hands but as far as effectiveness, this study shows us that the temperature of the water used did not matter", said Donald Schaffner, professor at Rutgers University in the US.
What's more important, they said, is that people scrub their hands with soap for at least 10 seconds.
They also said that using antibacterial soap instead of normal soap didn't make much difference either.
The song takes about 20 seconds, which is the amount of time people should wash their hands.
The findings are important, the authors say, because the Food and Drug Administration's guidelines for restaurants and food establishments recommend that plumbing systems deliver water at 100 degrees for hand washing.
Despite the study only including a small number of participants, executive director of the Canadian Public Health Association (CPHA) Ian Culbert says it was nonetheless a well-designed study that was still able to offer an interesting perspective on the long-debated issue.
Their guidance focuses on rubbing hands together in various ways to make sure each surface of each hand is clean.
Scientists have poured cold water on the theory that only a hot bath of shower gets you clean. A new study suggests you can turn the heat down a notch because cleaning your hands in cold water is just as good.
Hand washing is the simplest, most basic way to stay healthy.
However, the researchers did admit that their study sample was small, and that more extensive studies are needed to determine the best ways to wash potentially harmful bacteria and germs off hands - and the rest of the human body.
"I think this study indicates that there should be a policy change", he said. "Many hand-washing recommendations are being made without scientific backing, and agreement among these recommendations is limited, as indicated by the major inconsistencies among hand-washing signs".