Thanks all. You've sated my curiousity. I actually learned something...

For Sandra's entertainment... After flushing the toilet three times wondering if there was something wrong with me , I noticed the placard on the bathroom vanity at the brand new Hampton Inn in Greenville Mississippi @1999:

If you're wondering why our water's brown
It's the deep well aquifers under our town
You can bathe and drink without fear
'cause no one lives longer than the folks around here.