BB should turn the water OFF and give the HMs BabyWipes between 8am and 12 noon. Turn the water ON for half an hour at noon so the HMs can all go to the loo and flush. Turn water OFF again at 12.30 until 6pm and provide more Baby Wipes. At 6pm all HMs instructed by BB to have a communal bath in the swimming pool.
That should save some water.