On sunny days how long does it take for UV rays to pasturize let say 1 quart of water?
I would like to know that, as well.
Might be that most illnesses are related to improper human cleanliness practices.
I lot of backpacker's illnesses are caused by using household detergent and not rinsing thoroughly. There is seldom sufficient rinse water available to rinse thoroughly without directly damaging the water source. That is why we have the bio-suds products and are told to wash some distance away from the water source.
If really grimy, I use a non-alcohol wipe.
I've read that most water found in the back country is safe to drink.
I am not so sure about that. Beaver and turtles are carriers of giardia.
There is a "practice" of purchasing and releasing turtles every month. I told the San Francisco Public Health official I knew of one Tibetan Lama who said he purchases turtles every month and then releases the turtles on the drive between San Francisco and Oregon. The San Francisco Public Health official was appalled at the thought I was making a slur against Tibetan Lamas.
I seldom trust a natural water source, unless remote.