Almost everyone prewashes dishes before they put them in the dishwasher. This could be a waste of both time and water.

According to a new survey by the makers of Cascade detergent and Marie Claire magazine, 96 percent of those surveyed spent an hour or more a week prewashing dishes before loading. They used an estimated 12.5 gallons each time they prewashed - an unnecessary step, according to dishwasher manufacturers.

That extra step can add up to more than 87 gallons a week.

If every American household with an automatic dishwasher stopped prewashing before loading, the potential water savings could exceed 130 billion gallons a year, according to Cascade research.

Modern dishwashers are a lot more efficient than doing dishes by hand. Energy Star-rated dishwashers use on average 4.25 gallons per load, compared to 27 gallons for hand dishwashing that same load.