So, in looking at this idea of installing RPZs on a washing machine line--this is more of an academic question, actually, if you'd indulge me.

Our building president, whose judgment I don't trust (she tends to seize on the most dramatic reason to not do whatever it is she doesn't want to do, and play it up really big), said that if we had installed individual 3/4" RPZs on the lines that go only to the washing machines, it would have meant that it would take a really long time to do a load of laundry.

I'm guessing because the RPZ would cut down on the water pressure, so the washers would fill less quickly (they're 15 gallons only).

Is that true? How much time would it add? They fill up 3 times (1 wash, 2 rinses) in a 40-minute cycle now.