My grandmother had a spring across from her waterfall. Her family, including my mother and aunts, drank from that spring since 1870`s They all died in their 90`s. No cancer, no TB, no influenza, no major diseases. My sister is a college grad water expert. She had a bottle of it tested at her lab. It was full of selenium. It was so cold in the spring no harmful bacteria were present... The lab said it was probably due to the cliff granite rocks it came thru acting as a filter. When I was a kid I drank from that spring also, and also from a deep-running spring-fed lake whose temperature at the bottom was near freezing all year round that no bacteria could live there, according to the scientists who scuba dived and brought up water samples from 300 feet deep. They said it was a “Dead Zone” hypoxic low-oxygen fast-flowing lake.