Your dirty hands can harbor millions of germs, but simply washing your hands with regular soap—making sure you vigorously rub them together for 30 seconds—will slough enough microbes down the drain to cut that number to the tens of thousands.
Assuming you don’t then lick your hands, you’re probably safe at this point, but there’s still some risk. “Most pathogenic organisms cause disease when the numbers ingested are in the thousands to 10,000,” says Dial Soap’s manager of microbiology, George Fischler. Dial lab tests have shown that antibacterial soap, which most frequently uses the germ-killing agent triclosan, will, if used properly, reduce the number of germs on your hands to a few thousand.
But Allison Aiello of the University of Michigan School of Public Health isn’t convinced. Her lab, she says, has found no germ-killing benefit from triclosan over regular soap alone, even after three minutes of scrubbing.
If you’re worried about runoff from antibacterial hand soap creating super-bacteria, your drainpipes are safe. Aiello and her colleagues have identified only a few bacterial strains resistant to triclosan or other household antibacterial products, and those were only in controlled laboratory settings primed for growing bacteria.