WATER

 you can live a long time without food. but not long without water.
before the advent of gadgetry the way we did it was this. we'd simply
filter the water through out Tee shirt. if we were near sand we'd
use sand too. then we'd hard boil it for at least three minutes and
then drop in a few coals from the fire to bring back the taste.
heres some tips.. a SPONGE is a great device to collect water with.
have one in your bag.
you can BOIL water in a PLASTIC CONTAINER as long as you don't let it sit
directly on the coals. the water dissipates the heat so the plastic
doesn't melt. you don't have to boil the water. low grade heat for a
longer time works. ez to do with solar.
 carry a SHEET OF CLEAR plastic. it has many uses. you
can use it to make a solar collector to steralize water. you can dig
a hole and put a cup etc. in the middle of it and cover the hole
with the plastic. put a stone in the middle on top and seal the
edges with soil. the water in the earth will heat up and distill on
the undersideof the plastic and drip into the cup. if you have a
supply of water ( even saltwater) you can re-plenish the earths
water by pouring some into the hole ocassionally. you can also use
the plastic sheet to collect rainwater by doing the same thing but
punch a small hole where the stone comes to a rest in the center of
the plastic so the rainwater drips into the cup or canteen or
whatever. next we cover DEVICES for water acquisition.

i use COLLOIDAL SILVER as a dis-infectant. and don't forget just AERATING the water helps to kill bacteria too. just shake h..l out of it. and for longer term/stationary waterfiltration consider this
http://www.potpaz.org/pfpfilters.htm
i have never owned one but have seen them milsurp but some armies ( canadian i think?) used a water filter BAG that was simply dense weave cotton denim, sewn into a long bag. they filled it with water, added dis-infectant and hung it up. the bottom end was sewn at an downward angle and cut so that the filtered water would drip from the corner. they filled it with water and hung it up with a catchment container under it. put more likely everyone would just hold thier canteen under the stream of water. MAKE YOUR OWN. it's simply a blue jean leg open on one end, sewn at a downward angle at bottom, cut off the angle. put in a paracord cinch at the top. supply several people with filtered water. costs negligable, rolls up fits in pack.
then theres the $2 water filters at wallyworld. they are like two 2gal plastic milkjugs one atop the other with a activated charcoal filter element between them. pour unfiltered water in and get filtered water out the faucet in the bottom of the lower one.
while this will do a good job of filtering the water and you can add dis-infectant after, the filter elemnt won't last long if you filter dirty water with it. theres a better way to utilize this device. whats good about the charcoal element is that it restores the flavor to water. so i have used them like this.... filter water first. pastuerize next. and pour the result through the charcoal last adding dis-infectant as a precaution.
they make floaters for spas that use SILVER and COPPER bb's in an depletable elemnt to dis-infect the water. i put a couple silver bb's in each of my canteen/water carriers. even in storage. just for safe measure. i also have a small homemade solar colloidal silver generator that i carry in my pack.
i use re-cycled dis-posable aluminized plastic bladders like commonly
found in BOXED WINE etc. they are suprisingly rugged ( you can cut one
but it's difficult to tear one) are insulated and have a little faucet
at the bottom. they fold up small. i stash them EVERYWHERE.in all my
vehicles, coats packs etc. to carry them i use blue lean legs sewn at
the bottom as already posted. with the bladder of filtered water
stored in the wet denim bag it acts like a COOLER to boot.

ps. the water will smell/taste like wine for a loooong time :).