It's best to wash dishes by hand. The key is that you don't keep the water running the whole time. Instead, use put a small amount of dish soap in a large mixing bowl and run the water into it to make suds. Fill up the bowl and turn off the water, and use the soapy water to wash the dishes. Then simply rinse the dishes when you're finished. That will use less soap, less electricity, and less water than any dishwasher possibly could.