I used to pass by a sign in some blink town in Tennessee south of Murray that boldly stated that town had fluorinated water by order of the state health department. I wondered if other backwoods towns had similar signs around Tennessee and what lawsuits or arguments prompted the signs. It had to have been from the 1950s or 1960s, but it did always make me chuckle.
The LWC has a pretty good website at http://www.lwcky.com/ that does a good job of explaining the whole works. People here are right, chloramine is present in the water and it is readily detectable at the tap. I used to get results around 2.5 ppm when I ran total chlorine analysis for a wastewater lab.