Water conservation is a hot topic, and one common question is the comparative water efficiency of dishwashers versus hand washing. If you really want to save water, is it better to wash by hand in the sink or to use a machine? The answer is not as cut-and-dry and you may think; it really depends on several factors, such as load size, the type of dishwasher you use and what hand-washing practices you employ.
Dishwashers: Advantages and Considerations
If you have a newer dishwasher, especially one that is Energy Star rated, you may indeed be able to conserve more water with it than you would by doing your dishes the old-fashioned way. A study at the University of Bonn, in Germany, has found that a modern dishwasher uses about one-sixth the water of someone washing the same amount of dishes by hand while keeping the water running.
A newer dishwasher uses about 4-6 gallons of water per cycle, whereas hand-washing may require twenty or so gallons. So, if you have a newer dishwasher and only run it when it's full, this is actually quite water-efficient.
A good way to save even more water is to cut back on pre-rinsing; most modern dishwashers have enough power to get food off dishes on their own. On the other hand, if you have an older dishwasher, it may save you more water to wash small loads of dishes by hand and use the machine only for big loads. These older models use more water - up to ten gallons per cycle - and require you to pre-rinse dishes.
Hand Washing: Saving Water the Old-Fashioned Way
It is possible to save more water by hand washing than by using a machine in certain circumstances. If you only have to do a handful of dishes every day, it may save you some water if you just do them by hand. This will save you from having to wait for days to fill your dishwasher, and it certainly saves more water than running your dishwasher when it is only partly full.
However, in order to really save water when hand-washing your dishes, you need to follow a few water conservation practices. If you have a double-sided sink, fill one side with soapy water for washing and one side with clean water for rinsing, then turn off the faucet. Instead of scraping pots and pans under running water, let them soak.
Dishwashers win, sort of
So, whether hand-washing or machine-washing will save you more water depends on how many dishes you wash, what type of dishwasher you have and whether or not you use water-conserving practices when washing by hand.
In general, an efficient new dishwasher is a good way to save water over hand washing. Keep in mind, though, that this it depends on only washing full loads and not pre-rinsing. For people with only a few dishes to wash, hand-washing may be the better bet, as long as you only run the water as long as strictly necessary. In either case, using water conservation tips will make your dishwashing more efficient and easier on the water supply.