Re: Drinking water tank water.
We use our tank water for everything. The idea of bringing enough bottled water for our 4-6 week cruises is unnecessary, impractical, and a huge waste of money and environmental resources.
We only cruise seasonally right now, and fill from trusted "first-world" sources. Our tank is SS, but is large, so we do try to fill only what we need. We do shock the tank each season, and use a basic carbon filter for taste, but I've no reason to be concerned about drinking directly from it. Heck, in our home waters (Lake Superior) we often drink directly from the Lake.
When we head off for places unknown next year I expect to filter direct drinking water using a katadyn hand pump. But I certainly hope to never be in a situation where I'm forced to fill our tank with water that is so suspect that I can't cook or clean with it.
Why go fast, when you can go slow.