At 1 ppm, fluoride is diluted in a million parts of water.
So, 1 ppm can be represented as:
- 1 inch in 16 miles
- 1 minute in two years
- 1 cent in $10,000
With the new HHS recommendation of 0.7 ppm, even less fluoride is actually present in the water, but still is sufficient for oral health benefits.