I'm sorry, you have my condolences. You are now the owner of a ticking time bomb with a $11,000+ fuel system design flaw and no warranty. Keep every fuel receipt, video record yourself draining the water separator every 5000 miles and keep what you drain out in a sealed, dated container, change the fuel filter every oil change using ONLY a dealer part, video record that, too, and keep the old filters.
I would not even CONSIDER replacing the fuel tank...it will reduce the already-slim chance Ford will cover a failed HPFP to exactly zero.