some time back i did an experiment, even drew up an algebraic formula but can't find it.
anyhow, i set the pump to a low flow and cleaned a window to my satisfaction and timed it and worked out the water usage. did the exact same experiment with a higher flow, and it worked out i cleaned the window faster and used less water! about 10% i think it was. obviously there's a few variables to consider, my opinion of satisfactorily rinsed might not be yours but that' basically irrelevant. what is relevant is how fast you can physically wash a window, a slow worker will waste water, a fast worker will waste time, and of coarse whether you turn off between windows, etc.
still, i think there's a potential to increase speed and save water
anyhow, i set the pump to a low flow and cleaned a window to my satisfaction and timed it and worked out the water usage. did the exact same experiment with a higher flow, and it worked out i cleaned the window faster and used less water! about 10% i think it was. obviously there's a few variables to consider, my opinion of satisfactorily rinsed might not be yours but that' basically irrelevant. what is relevant is how fast you can physically wash a window, a slow worker will waste water, a fast worker will waste time, and of coarse whether you turn off between windows, etc.
still, i think there's a potential to increase speed and save water