How much fluoride is needed?
In a temperate climate, such as in the UK, the recommended level to help reduce tooth decay is one milligram of fluoride to every litre of water (1mg/l). This is usually called one part per million (1ppm). This level is currently agreed to be the optimal level at which the benefits to dental health balance out any increases in fluorosis. In other parts of the world other levels may be used.
