Two pros for having fluoride in the drinking water supply are its ability to help prevent cavities and the easy access underprivileged citizens have to this fluoride supplementation. Cons include the ingestion of too much fluoride and difficulty for people to avoid consuming it in their water.
Fluoride is a common ingredient in many tooth hygiene products, such as toothpaste, floss and mouthwash, because it is extremely effective in preventing tooth decay. This is great for people who can't afford regular dental care, such as visits to the dentist or the ability to obtain toothpaste on a regular basis. The presence of fluoride in the drinking water allows underprivileged people to have some protection from cavities that they wouldn't otherwise have.
On the other hand, for citizens who do see the dentist regularly and use toothpaste and mouthwash daily, having fluoride in their drinking water can cause an overdose of fluoride. The overconsumption of fluoride can cause spots or ridges on teeth. Also, people with kidney disease are advised to avoid fluoride whenever possible, presenting them with problems accessing the readily available drinking water supply. Since the United States has fluoride in its water system, it becomes extremely difficult and expensive for these patients to avoid fluoride in their drinking water.