FWIW- when you buy a new washing machine it usually comes with
black rubber hoses. We always replace those with the stainless braided
ones. I take those black rubber hoses and cut them in half. This gives
me 4 short water hoses with a faucet fitting on one end.
I use one of those to fill my fresh water tank. It works great and I
never get "blow back" until my tank is absolutely full. I use them in my
garden to fill buckets and watering cans at a faucet.
AND-- I can stick one in the drain hole in my water heater to flush out
most of the crud when I'm winterizing. If there's a -few- grains of calcium or
lime or flakes from the anode left in there I don't care. I get out most
of it out and move on. That's good enough for me!