Columbia tap water : columbiamo
I vaguely remember my Geology instructor at MACC (a retired public works man who definitely knew his stuff) claiming that indeed, Columbia/Boone county-area tap water was some of the highest quality in the United States, but only because of a flaw in the design of the infrastructure that results (at some point, pre-processing) in sewage being mixed with the source. So the actual filtration facilities had to be overbuilt to compensate.
It's been almost 10 years ago now and I failed that class twice, but I remember this particular bit quite clearly because it was the only time I ever witnessed the guy laugh lol.