call me crazy but when i was a young tike the small rural town that i grew up in got its water from a mountain spring that ran directly into the water lines. I was about 12 when a group of college students tested the water and found that because the water ran for approx 1 mile before entering the pipes the water was found to have giardia in it. the entire town was told to boil their water and the drinking fountains were turned off at schools we were told to bring canteens w/ boiled water to school to drink. now the water had been loaded with giardia for at least 50 years. the towns folk just filled their canteens with water from the faucet and sent their kids to school. I to this day have never had an issue with giardia in streams ( and i have drank out of a lot of streams) now crypto on the other hand thats a b?tch. ps sorry about the grammer and spelling I've been up for over 24 hrs and needed somthing to help keep me awake.