Run only full dishwasher loads. A relatively small volume of water completes a cycle in dishwashers. Most dishwashers fill with 2 or 3 gallons of water during each cycle. Depending on the cycle you select for washing or rinsing, the dishwasher fills and drains 4 or 5 times using from 12 to 16 gallons of water during the complete cycle time. This amount of water is continually recirculated through the spray-wash arms and filter system of the appliance to clean the dishes.
Many people find that one running does the day's dishes.
This means dirty dishes, glasses, snack plates, pots and pans, and preparation utensils can be put into the dishwasher until there are enough accumulated for a full load. This reduces the use of water, since less is used to run the dishwasher once a day than would be needed when clutter is washed by hand frequently throughout the day, usually under constantly running water. It takes just as much water to run the washer empty as full. Good machine loading practices assure proper circulation of spray for effective cleaning. Look for loading instructions in the use and care manual for your particular model.