ANSWER: Newer dishwashers use an average of 3-4 gallons of water.
More Info: Dishwashers manufactured after 1994 use between 8 and 14 gallons of water per load. To earn an Energy Star rating since August of 2009, a machine is required to use 5.8 gallons of water or less. Most models average 3-4 gallons.
Although most people find it hard to believe, a dishwasher does use less water than washing dishes by hand. Most people who wash dishes by hand do so, at least, twice a day by filling a sink with hot soapy water and leaving the water run to do the rinsing. People who use a dishwasher, normally wait until it is full to run the cycle. For most families, this will be no more than once a day and may be only two or three times a week.
Energy Star Ratings
Modern manufacturing techniques are making dishwashers even more efficient. Dishwashers manufactured after 1994 use between 8 and 14 gallons of water per load. To earn an Energy Star rating since August of 2009, a machine is required to use 5.8 gallons of water or less. For some appliances, the actual water use is half that required to wash the same dishes by hand.
Water Saving Features
Another way that modern dishwashers save water is through specialized cycles.
- For lightly soiled dishes, most of the newer dishwashers have a shortened cycle that uses less water.
- They also allow the user to skip pre-rinsing. Simply scraping off large scraps of food, as if preparing to wash the dishes by hand, is all that is required. This can save up to 20 gallons of water per load.
- For people who require two or three days to accumulate a full load of dishes, most newer machines have a rinse and hold feature that gets rid of food that may be harder to remove after drying out. On most dishwashers, the rinse and hold cycle will only use one or two gallons of water.
- Some energy efficient dishwashers also have a "soil sensor" to automatically adjust water usage depending on how dirty the dishes are in each load.
A new Energy Star rated dishwasher can save as much as 5,000 gallons of water per year over hand washing the same amount of dishes. It will also save approximately $40 in utility bills and 230 hours of time.