I am planning to use Katadyn Micropur tablets to purify water in 1 liter bottles. The question is if I dip bottles in a stream, drop the tablet in the bottle and dry off the bottle with a towel, would any pathogens that get were dried off by the towel die in a few hours or do I risk contamination by drinking from the bottle (i.e., lips on bottle submerged in contaminated water but dried off and having waited a few hours)

Bump

Waterborne pathogens die when they dry out.

There is a technique to treating water in, say, a Nalgene bottle. After the treatment cycle (3-4 hours or more, depending on treatment option, water temp, etc.), invert the water bottle, unscrew the cap, and let some water flow (trickle) out. This (I believe) flushes out any pathogens that weren't in the bottle proper, but hanging around on the outside in the thread grooves (where your lips would touch when you take a swig)...

Edited by NightMarcher on 05/09/2011 18:52:39 MDT.

Protozoa such as Cryptosporidia and Giardia have protective cysts -- they remain viable even after being exposed to air for a while. The inverted rinse method works best if you are using bleach or chlorine dioxide to treat your water. With other treatments you are likely just mechanically washing down the bottle threads. Some people carry a small plastic cup to dip water out of the stream with, pouring it carefully into the treatment container so as not to splash. This also has the advantage of letting you skim the water surface, which can be quite important when using highly turbid sources like glacial streams and lakes.

So for washing hair/body do you bother with water treatment or just use the water directly?

Depends. Are you using a cattle trough or stream frequented by cattle? Perhaps not in that case. In most situations it's OK as long as you don't ingest the water.