Pure water

Don't go out and buy expensive filters... make a solar one yourself:
[You must be registered and logged in to see this link.]

Or use tank water from the run off from your roof.

In the long term... well if anyone has any ideas how to get municipal water to people clean and efficiently... let us know.

Also, for those emergency situations... you can get a life straw:
en.wikipedia.org/wiki/LifeStraw

- Pure water is the world's first and foremost medicine. - Slovakian Proverb