Gonna call you on this one MJ. I remember reading about this study and thought it was a pile of horse potatoes. So I looked and looked .... while I didn't find the study, I did find some pseudo reference to it that reflected the numbers of gallons of water used when washing dishes by hand vs. the dishwasher.
It turns out that using an eco dishwasher just right can save a lot of water and power compared to the AVERAGE person washing dishes. BUT! A person that is conserving water while washing dishes can save even more!
The doing-it-by-hand technique that beats the most eco dish washer under any circumstances is pretty simple: use a dishpan; run just a tiny amount of water (quarter cup?) to wash the first thing. Then use a tiny amount of water to rinse that one thing, with the rinse water running into the dishpan. As you are on to the fifth thing, you have a bit more soapy water in the bottom of the pan. So you can start washing bigger things. By the time you are done washing and rinsing everything, there should be about two quarts of water used.
In this one, they washed 12 place settings, or 140 items. The average hand washer used 63 litres of water (9 medium sized bowls, or 16 gallons). Obviously most of us can do better than that. In fact, in the study, the Germans averaged 46 liters (and the least amount of time washing up. Gotta give it up for German efficiency...)
Look at the graph for how energy use goes up in manual washing as the volume increases, though. You can easily beat the dishwasher with 3-4 place settings, but then you wouldn't be running the dishwasher full.
In my leanest attempts to clean a *full* dishwasher load, between sudsing and rinsing, I ended up filling the sink to the 3/4 mark by the end. I have a ten gallon sink, so that's 28 liters. Trying to be super careful with the water made it take about an hour. My dishwasher uses 15 liters and took me 5 minutes to load.
But maybe I just don't have Paul's fantastic technique. 2 quarts is definitely remarkable. I think a YouTube video might be needed!
Brave New Leaf - Everyman Environmentalism http://www.bravenewleaf.com
I didn't see Water Day mentioned in any of the US News, this article was in the Canadian press. Evidently it was started in 1992 by the UN as part of raised awareness about environmental safety and conservation. This year's theme was sanitation, one of the least commonly recalled and subtler details in permaculture design.
Peterborough Examiner, Canada - Mar 24, 2008
Saturday was World Water Day and a local group was reminding Peterborough residents that we are all in the same boat. "We're all downstream so let's take care of this precious resource," said Kathryn Langley, member of the Peterborough-Kawarthas Council of Canadians. The group was out at the Peterborough and District Farmers' Market where they had two tables set up providing information on water issues. "They (governments) need to know we are paying attention," Langley said. She was urging shoppers to send a message to Prime Minister Stephen Harper and Premier Dalton McGuinty. "Water is a human right and not a commodity," she said. The group is pushing for a national water policy that would include funding for public water infrastructure. "The money has to flow just like the water," Langley said. She said there needs to be a move from all levels of government towards protecting our water supplies. "We are sincerely concerned about the sustainability of our future," Langley said. The local group was one of 40 organizations around the country who were out campaigning during World Water Day.