Everyone has their own way of doing this. Me? I use about twice as much bleach as is normally talked about and I leave it in the lines, tank, everything for 24 hours when time allows. Then, I flush it really well. I just figure I want to kill everything possibly in there. I have done this for thirty years and never had a problem.
However, we are also one of those that just buy cheap bottled water by the gallon for coffee, tea, cooking and drinking. We most often boondock and often fill our tanks with hand pumped water in some remote national forest site. For 80-90 cents a gallon at the grocery, why take a chance?