My old mum used to say that hard water is good for you. (Don't know if it's true, it might cause kidney stones!)
Eliza, statistical studies show that populations in areas with naturally very SOFT water have a significantly higher rate of hardening of the arteries. These findings came out in the middle 1950s.
About that time, my grandfather, then in his mid 80s, was hospitalized for what boils down to hardening of the arteries, and one of his legs had to be amputated. He must have had some involvement of that in his brain, too, because he was somewhat out of his head.
My aunt Lucille, who worked at the Mayo Clinic in Rochester, Minnesota (my home town), when in his hospital room along with other family, thinking Grandpa was unconscious at the time, discussed these findings, which had just been published, in his presence.
Evidently my Grandpa was listening, playing possum at the time, and was confused about what he overheard. He thereafter steadfastly refused to drink water, because "it had poison in it", as he said when more or less conscious. He had evidently mistakenly processed Aunt Lucille's account of the hard and soft water findings.