Public Health · single question
What is the recommended community water fluoridation level in the United States?
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Correct answer: A. 0.7 mg/L (ppm)
The U.S. Public Health Service recommends 0.7 mg/L (0.7 ppm) of fluoride in community water — updated in 2015 from the previous range of 0.7–1.2 ppm. This level provides optimal caries prevention while minimizing fluorosis risk. If the natural fluoride level is 0.3 ppm, supplemental fluoride is needed. A child in an area with 0.3 ppm water would need supplemental fluoride — typically 0.50 mg/day for ages 3–6.
- A. ✅ CORRECT – 0.7 mg/L is the current USPHS optimal community water fluoride recommendation.
- B. ❌ 1.5 ppm or above can cause fluorosis — exceeds the safe recommendation.
- C. ❌ 0.3 ppm is below the optimal level — areas with this level may need supplementation.
- D. ❌ 1.0 ppm was the previous upper limit — the 2015 guideline consolidated this to 0.7 ppm.