my mother did laundry with a wringer washer, and she used to re-use the rinse water for several loads. She put the drain hose into the cement laundry tub and stored the used rinse water there; then for the next load, she used that same water for the rinse.
But I can’t see a commercial laundry doing that – where would they store all the rinse water between loads. Also, you had to be careful of the order that you washed loads – dirty overalls were the last load. How would you do that in a commercial laundry?