Re: Drinking water tank water.
While I think people go overboard sometimes in the quest to sterilize everything, I do think common sense dictates that you should not drink water from the frog pond! Giardia is no fun and to complicate matters, is rare enough so if you get a case, it is very likely that it will be misdiagnosed. A buddy of mine got it drinking water from a ski area fountain and seriously thought he was dying until doctors down south brilliantly recognized what it really was. This took months. In these parts we call it "Beaver Fever."
I always try to leave with 3-5 gallon containers of my own "spring water" from the artesian well here at home just because it is great for drinking and has no chemicals in it but I would not hesitate to drink the chlorine-dosed water from the 75 gallon tank which I reserve for dishes and showers. I also keep a good sized bottle of iodine aboard which is said to kill more bugs than chlorine but have never tried it.
Alberg 35: With a philosophical flourish Cato throws himself upon his sword; I quietly take to the ship.