Is it OK for hikers and backpackers to drink water from remote streams?
No. These streams often contain Giardia, a microbe that cause an illness called Giardiasis. Giardiasis is characterized by severe diarrhea that can last several weeks. In addition, disease causing bacteria (Giardia is not a bacteria) from wildlife might also be present in remote streams. Chemical pollution is not a problem in remote streams, because a person generally would not drink enough water to cause sickness.