Our boat carries 77 gallons of freshwater and we have no water maker. Over the years, we’ve developed a number of techniques to conserve water that allow us to cruise three or four weeks without replenishing. On our summer cruise this year, we added another to the list: an alcohol-based waterless hand sanitizer.

While we’re not hand-washing fanatics, we don’t want to be too lax either. But when we’re in water-conservation mode, proper washing with soap and water consumes far too much water. It’s not just the water used in washing, but also the water wasted in running the tap until the water is hot. We could capture that water as we do for showers, but that’s a pretty serious hassle just for hand-washing. And sometimes we can’t properly wash with soap and water because the furnace isn’t on and we’ve not run the engines for a while, so we simply don’t have hot water. We could boil water, but that is getting back into the serious hassle category.

Waterless hand sanitizers have been popping up in public areas everywhere these days, particularly in hospitals, the workplace and schools. But are they as effective as washing with soap and water? In certain cases, yes, and they have some advantages too.

Alcohol-based hand sanitizers must be approved by the FDC to be sold in the US. The Center for Disease Control includes them as an acceptable alternate form of hand hygiene. In Better: A Surgeon’s Notes on Performance, Gawande describes a hospital that dropped its MSRA infection rate to zero through the use of alcohol-based hand gels, among a variety of other practices. Hand gels are particularly effective in hospitals because people are more likely to use them. Proper hand-washing between every patient takes too long and people just won’t do it. Atul Gawande notes that hand gels with an alcohol concentration of  50 to 95 percent are more effective at killing germs than hand-washing.

Washing with soap and water doesn’t actually kill germs—the friction of washing pulls germs and dirt from the skin and they are rinsed away with the water. The hotter the water, the more effective the lather and rinse. With hand sanitizers, the rubbing action works the gel into the nooks and crannies on the hands and the alcohol kills germs directly. The germs fall off the hands, and the sanitizer evaporates. Hand sanitizers work more quickly than washing with soap and water, do not promote antimicrobial resistance, and can improve skin condition. Hands that are cracked and dry from repeated washing with soap and water can harbor more germs than healthy ones. Hand sanitizers kill most common germs that are transmitted by touch, but are not effective for removing visible dirt or food-borne pathogens.

We’ve been using Purell, but have also tried Kroger’s product. Although the Kroger product is less expensive, we prefer Purell because it seems to dry a little faster. Both contain 62% ethyl alcohol and should be equally effective. We started off with a 2-fl oz bottle as a tester, and later bought the larger pump bottles.