The optimum fluoride level in drinking water, as recommended by the Department of Health and Human Services and the USEPA, is what?

• A. 0.3 mg/L
• B. 0.5 mg/L
• C. 0.7 mg/L
• D. 1.0 mg/L

Answer: (C)

Fluoride is kept at about seven-tenths of a milligram per liter in drinking water because this level delivers strong protection against tooth decay while minimizing the risk of dental fluorosis for most people. It balances how much fluoride people actually ingest through water given different climates and consumption patterns. While the EPA sets a much higher enforceable limit to prevent toxicity, the recommended optimum for dental health is 0.7 mg/L. Levels much lower would reduce decay protection, while higher levels increase the potential for fluorosis with long-term exposure.