The dishwasher dilemma

Often I hear the argument that using a dishwasher reduce the use of water when replacing washing in the hand. We often calculate the better choice from a small scale perspective. If I do X now, I will reduce my use of Y. But does it really make sense if taking more than the water use into account?

I think we severely lack studies that undertake taking into perspective the total consumption of resources in our habits and production, from concept until it is implemented.

It takes 2.900 gallons (10.991 liters) of water to produce 1 pair of jeans (National Geographic, April 2010). I would modestly argue a dishwasher probably consume a bit more than a pair of jeans to produce when taking into account: extracting raw materials, shaping materials into parts, transport of parts, combining parts, packing parts, shipping parts, running the machine in use, etc. Additionally, advertising, packing materials, design & development, etc. should also be part of this equation.

A thought experiment.
For modesty sake let us say it takes a only equal to 1 pair of jeans (10.991 liters of water) to all aspects of making and buying a dishwasher. Let us also be large and assume the machine gets a life of 15 years. If you waste 1 liters daily from washing your dishes in the hand rather than in a dishwasher you would have "wasted": 365 liters x 15 years = 10.950 liters of water. Still less than the savings gained from buying a washing machine. The truth is probably closer to 1000 jeans, which would require a good 180 years of hand washing wasting of water to balance out.

It is the same thought experiment Daniel Quinns sketch in his book "Ishmael" asking: "What takes more resources to produce? A can of tomatoes, or getting it in the wild?" When stating something like that it also raises the question of how to feed the large population in our current situation without industry. And how about all the people whos work is dependent on continous consuming resources?
My suggestion is that we scientists and economists pay attention to these kinds of calculations to explore if there is sense in our current industry. My field of agriculture and livestock production could benefit from such studies. For example, is it really more efficient to farm livestock in high densities rather than on permanent grazing areas? Or, is plowing necessary when all the side effects is taken into account?

Manley P. Halls lecture on "Value" kind of sums it up. If the time you save on buying a modern convenience such as a dishwasher is used for something without value, such as watching television, the time washing dishes is better invested.

Further reading