I suspect some fairly nasty chemicals are released when a common water
bottle is heated this way, but I would rather take my chances with them than
with the parasites. Filtration without a highquality, storebought filter is not as ideal
as purification because filtration likely won’t remove harmful micro
organisms from the water. What filtration will do is remove larger mat
ter such as dirt and sediment, sticks, leaves, and any bugs or critters
living in the water.
The simplest way of filtering or clearing stagnant, foulsmelling
water is to place it in a container and let it stand for 12 hours or so. There
are several, more active methods of filtering; most involve letting the
water flow through layers of different types of material such as pebbles,
sand, cloth, and charcoal. You can layer these materials over a receptacle
with openings at either end, such as a piece of bamboo or hollow log.
Construct your filter so that the water passes through successively
less porous layers of filtering material over a receptacle. A typical filter
might begin with pebbles or stones, followed by sand, cloth, and then
crushed charcoal (not ash), which is by far the best filtering medium avail
able. As with most filtering systems, the water will become progressively
clearer the more you filter it.
RegionSpecific Water Considerations
Arid Regions, Deserts, and Canyons
Searching for a primary source of water should be your main goal, but in
the world’s drier places there’s less chance of finding one. For this reason,
you’re likely limited to creating stills and ground wells to collect water.
A prevailing thought is that your best bet for finding water in arid
regions is to look in valley basins or at the bases of sand dunes. But knowl
edge of your particular locale may tell you something different. When I
was in the Kalahari Desert, I learned that the best place to find water was
not at the bottom of the sand dunes but rather at the top. The hills there
act like wicking agents and actually draw the water from the ground up.
So it made more sense for me to look for plants (which had water in their
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