Is there a point beyond which water cannot be consumed even if you boil it? Assuming no chemical contamination, can you boil water to make it potable no matter how long it has been stored? The reason I ask is that I can envision a scenario where I have a whole lot of propane, a stove, a metal pot, and 40 gallons of water that has been stored at +90 F. for 3 months. Suppose that water is literally dripping with algae and assorted creepy-crawleys. Can it safely be drunk after straining and boiling, or will toxins (botulism, salmonella, etc.) which cannot be removed by boiling build up in the supply, thereby making it deadly?