Fluoride
I’ve never lived anywhere fluoride was added to water — be in rural living at my parents house or nowadays in the Town of Bethlehem where they don’t fluoridate the water. But it seems like teeth decay is a really bad thing as you can’t grow new ones, dentures are expensive and costly to get, and dental insurance even when you work for government is quite limited.
It doesn’t seem like fluoridation of water is particularly costly or harmful. Most fluoride in wastewater is pulled out by sewage treatment plants through ordinary treatment. It’s only about 5 lb of fluoride added to the water for a million gallons of water produced. Yet, bad teeth can have a real negative impact on people’s lives, especially with the poor coverage of dental care in current American health system. If we aren’t going to fix dentistry, then we should at least ensure the water most people drinks helps keep their teeth healthy.