Fluoride may occur naturally in water or it may be added in controlled amounts.  Some fluorosis may occur when the fluoride level exceeds the recommended limits.

Acceptable results: The current health standard is <4 ppm.  A fluoride concentration of 2 ppm in drinking water effectively reduces dental caries without harmful effects on health. In rare instances, the naturally occurring fluoride concentration may approach 10 ppm.  Such water should be defluoridated.

Sources: Natural and human added.

Recommended testing: If considering adding fluoride to water supply or if in a risk area of over fluoridation.