I too only use standing water to wash both RC and FB prints that I make and this is despite having running water in the bathroom, but I think it is an awful waste of water. Also, for decades, I have used the Ilford method of washing film using four changes of water.
For my prints for a long time now, I've only done three changes of water at about 25 degrees Centigrade, leaving ALL prints for three twenty minute soaks, agitating occasionally. I then using the last soaking water as the first for the next set of prints. Initially the prints were put in the bath tub and now a Paterson upright print washer.
RC prints are put straight into the water whilst FB prints, after a brief wash in water and then in either sodium carbonate (washing soda) or sodium sulphite solution for about ten minutes and then into the wash bath.
I've only recently started mixing up a residual hypo solution from the Darkroom Cookbook and am now testing my prints to see if they've had a good wash and results are good.
I have done this wash procedure since when I started in the early 1970's and although the prints from that period are not anything inspiring, there are no stains of any sort on any of all the FB prints done at the time and since.
I'm sure there will be, as there are with certain questions, numerous replies giving different methods and times.
Terry S