I do realize everyone before me has posted pra[c]tical paragraphs on the subject of water but to be honest water is a simple concept on the theory of 2012, its going to be everywhere just as it is today. Lakes, rivers, streams, rain, and a million other forms of moisture.
It will be everywhere as usual and it will also be virulently toxic from radiogens, blue-green algae, sulfuric acid, arsenic and heavy metals. But don't take my word for it. Soil and bone testing conducted at 11500 years, 22000 years and 34000 years ago confirms it. People living back then died because they were simply unable to find or filter any water that had not been contaminated. This is why I recommend storing it now
I think the main concern for a global catastrophe is of contamination. Either nuclear, toxic, or biohazard I think people should be concerned with a simple system to treat ANY and ALL water before they drink it if this situations occur.
If you can tell me what this simple system is that will run on a daily basis and convert poisonous water to drinkable water each day I'd really like to hear it.
If I were to drink from water that I know had been contaminated with biological, chemical, and radioactive elements I would effectively use a systematic approach to relieve each infliction.
Except those conditions are not cured as easily as videogames would have you believe. In real life, you just die, period. No Rad-Away or RadX. Not drinking such things at all is a much better policy.
Boiling to kill most biological life, then running through charcoal and other toxin filters then finally adding Potassium Iodide or a similar substitute to alleviate most if not all of the radiation.
Potassium Iodide is used to protect the thyroid glands and has nothing to do with water filtration.
Creating your own system is key because certain people are willing to camp and take the time for this type of preparation while others are going to be going berserko when the poo hits the fan. For the latter there are complete water additive solutions that can be used to be an all in one. But I would not suggest these solutions for a long period of time because they will cause gestational problems. The simpler you keep your milk eggs and bread the better.
I have no idea what that paragraph means. Doesn't really constitute a complete thought and arrives at no conclusion. Sounds like you are thinking out loud and not very well, either.
I give you 9-to-1 odds you are dead before you are able to get out your coffee filter papers. If I were you I'd try thinking a little harder about this problem.
Water is very close to the #1 concern every single day and is anything but "simple." Neglecting it in your planning is tantamount to picking out your coffin in advance.