Water from a mountain spring or creek tends to be clean enough to drink. I personally never treat the water if I am in the mountains and far from civilization (

Water from a mountain spring or creek tends to be clean enough to drink. I personally never treat the water if I am in the mountains and far from civilization (live in Colorado) even though there is still a chance I could get sick. However I will always treat that same water with iodine if it is sitting in a lake/pond or close to civilization because the likelihood of disease goes up significantly.