You run out of water on a long, hot dayhike. You find a full water bottle trailside, and also find a clear running stream. Drink from the stream, drink from the bottle, or abstain?
Submitted by - Tom - Altadena, CA
Your question overflows with relativity: Since it's a day hike, you're probably not that far from water, so why risk a drink from questionable sources? On the other hand, if you're feeling weak from thirst, a drink might be worth the relative risk. Generally speaking, running streams are relatively more risky than deep pools. In deep pools, germs tend to sink to at least several inches below the surface. In streams the germs are tossed all around. There's a good chance the water in the bottle is relatively safe, if you assume the missing owner disinfected the water. Give the mouth of the bottle a thorough wipe first and let it dry in case the last drinker was packing some nasty oral germs. And next time pack more water for your day hike.