The average top-loading washing machine uses about 40 gallons of water per load while the average front-loading washing machine uses 20-25 gallons of water per load.
More Info: How much water a washing machine uses depends primarily on whether the unit is a front or top loader. Most top-loading washing machine tubs are stationary with a twisting agitator in the middle. Therefore, top-loading washing machine tubs must be completely filled to wash clothes effectively. A top-loader's water usage may be decreased by 30-50% if equipped with a suds-saver. This device saves most of the sudsy water for later loads, but is probably most efficient when clothes are only mildly dirty. In contrast, front-loading washing machines have a rotating tub lying sideways. As the tub turns, the laundry tumbles about, decreasing the amount of water needed. This is why most front-loaders use 40% less water per load than top-loading washing machines.
Washing Machines Are More Efficient Today
Water efficiency has progressed in the creation of washing machines over time. Older top-loading washing machines use 50-60 gallons of water per load, while older front-loading washing machines use 33 gallons. Currently, most top-loaders use 40 gallons and most new front-loaders 17-28 gallons of water per load (though some small front-loaders use less than 10gal). The University of Leeds has created a washing machine that uses one cup of water. The inventor, Professor Stephen Burkinshaw, hopes this machine will begin a change in the way people do laundry and believes it will be particularly useful in drought-prone areas such as Australia.