Objectives  To investigate the content of fluoride in drinking water after the Water Improvement Project being conducted in rural area of Beijing, and to provide important technical support for water improvement in the future.

Methods  Stratified proportional and randomized sampling method was used to select drinking water samples from the rural areas of 12 counties of Beijing in 2009 and 2010. The concentration of fluoride in drinking water was surveyed according to the project.

Results  A total of 1 269 in 3 384(37.5%)water supply departments which covering 27.2%(1 665 401/6 127 050) of rural population were investigated. The median of fluoride concentration in 4 888 drinking water samples was 0.29 mg/L (0.01~3.22 mg/L). Fluoride concentration in 84.0% of drinking water samples was in the range of 0.01~0.5 mg/L, but the median of fluoride concentration in Shunyi County and Tongzhou County were relatively higher. The fluoride concentration of 64 drinking water samples from 34 water supply departments which covering 33 683 rural population was over 1.0 mg/L, and 44.1% (15/34) of samples were collected from local fluoride epidemic monitoring points. No statistically significant difference was observed between the concentration of fluoride in the finished water and tap water from underground water or surface water during dry or wet seasons.

Conclusions  Most of rural areas in Beijing were located in low fluorine area, but the fluoride concentration of drinking water in some regions is still slightly over the standard after water improvement projects being conducted.