There are many brands of dishwashers on the market, and each has its own water usage rating. The least water-efficient dishwasher is the GE GDT655SMJES, which uses 3.5 gallons of water per cycle. However, this dishwasher is still relatively efficient compared to other models on the market. The most water-efficient dishwasher is the Miele G4975SCVIK2OXXL, which uses just 1.1 gallons of water per cycle. This makes it more than three times as efficient as the GE model! When choosing a new dishwasher, be sure to consider its water usage rating to ensure that you are getting the most efficient model possible.