But "they don't clean as well" is a bit of a myth. More water requires more soap, and as it turns out, shuffling clothes around with *proportionally more soap* and *less water* leads to better cleanliness for the vast majority of stains.
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Think about it: if my washer only uses 1 gallon of water, but yours uses 5 gallons of water, your soap is 5x less effective than my same soap.
Its not the "water" that cleans, its the soap after all. With one exception: caked on mud prefers water over all other solvents.
But with regards to blood, sweat, grapes, tomatoes, and "typical" stains, its not the "water" that does anything. Its the soap. See ConsumerReports.org testing (ketchup tests and whatnot), as well as efficiency numbers that they've tested.