Natural water sources

All water from natural sources must be treated before you drink it, even if it looks crystal clear: it can contain Giardia, Cryptosporidium, bacteria, or viruses. Choose in this order:

1. Rain collected directly in clean containers or on a clean tarp. It is the cleanest; still, treat it.
2. Springs at the point where they come out of the ground.
3. Running streams and rivers, better than standing water. Take water away from roads, livestock, campsites, and drains.
4. Lakes and ponds, take water away from the shore and from algae.
5. Dew and vegetation: at dawn, wipe a clean cloth over dewy grass and wring it out; useful only for small amounts.

Signs of water nearby (FM 21-76)

• Greener, denser vegetation at the bottom of gullies and valleys.
• Trees such as poplars, willows, and sycamores, which grow near water.
• Animal trails that converge downhill, especially at dusk.
• Birds that fly low and in a straight line at dawn or dusk.
• In a dry streambed, dig on the outside of a bend: sometimes there is moisture beneath the surface.