more ideas from the archived section:
http://www.projectavalon.net/forum/showthread.php?t=509
water filters are great, but two things are of utmost importance:
1 - ease of transport
2 - simplicity
until we know what the future will hold, i think that the ability to transport your water filter/water purifier device is most important. anything requiring electricity or replaceable filters isnt a good idea, especially if we have no more access to stores or electric power.
in the worst case scenario, we might have to escape into the woods with a backpack with only the least amount of supplies to steer clear of some military goons rounding us up for FEMA camps.
digging a hole 6 feet minimum away from a moving stream and collecting the water that seeps in, then boiling that water is generally considered safe. all youll need is a shovel and a pot to boil the water.
ive heard that a 1/4 tsp of bleach will disinfect 1 US gallon of water. iodine and silver colloid will also disinfect, with silver colloid being the best choice.
the water cone i listed doesnt require any energy except the sun, but it might be too bulky to carry. solar stills, dew collection, and digging/boiling are the easiest ways to obtain clean water.
if we know that we will stay where we are in the event of some kind of emergency, then water filters will do just fine. i like to take it to the extreme level so that im covered in the worst case scenario.