A good dishwasher (for me anyway) uses 10-12.5 gallons of water on the normal cycle and runs all the wash arms at the same time without varying motor speed or having the pump pull air or water with cavitation.
If you really want to save water do what commercial DW do - re-use the rinse water. Collect the rinse water in a sump, start the cycle and heat the water via an in sump heater. Wash through a pair of high pressure wash arms that blasts away dirt. Drain, then start the water inlet temperature booster. Open fill valve, run the water through the booster where it goes to 185*F then route this heated water through a second set of spray arms that fans the water jets spraying down all dishes and utensils. Water collects in the sump for the next cycle. If the sump needs a top off or is empty water valve is opened to fill the sump then a pressure switch satisfies to start the sump heater.
I know Jackson under-counter glassware DWs (among most others) use this scheme. It was another machine I assumed the wiring diagram would put a rapid advance Kitchen-Aid to shame but only to be surprised it was not far off from that of a Potscrubber. Literally 6 cammed micro switches cycled all the components in a 90 second cycle.
You need a 240 volt connection to do all this- which I think all homes should have a 240 volt dishwasher. Even nicer would be if all homes had a 415 volt 3 phase supply. 7,200 watts at 3 phase 415 pulls 10 amps. A single 14/3 home run would get the job done. 5 minute normal cycle, 15 minute potscrubber cycle, 10 minute forced air blower. Rinse cycle has steam curtaining from all 4 edges of the door as the shrieking sound of an espresso machine is heard. Kitchen lights shadowed by thick steam.
Who has time to wait?