Effect of faucet-mounted water filters on the fluoride and calcium concentrations of tap water.

PURPOSE: To evaluate the effect of faucet-mounted water filters (FMWF) on the fluoride and calcium concentrations in tap water during their use. METHODS: A convenience sample of 15 different brands of FMWF was investigated (PUR, Brita, Waterdrop, Culligan, Engdenton, DuPont, Instapure, iSpring, OEMIRY, IVO, SJ WAVE, WINGSOL, ZeroWater, AIBERLE, MIST). Water samples were collected before the installation and after removal of the filters to determine baseline fluoride and calcium values. After mounting the filters, samples were collected after 1, 5, 10, 30, 50, 75, and 100 liters of water passed through each filter. Fluoride analysis was performed using a fluoride ion-specific electrode (Orion #96-909-00), while calcium analysis was performed using atomic absorption spectrometry. The data were analyzed using one-sample t-tests and one-way ANOVA. RESULTS: The study found significantly lower fluoride and calcium levels (P< 0.05) in water filtered through PUR, Brita, and AIBERLE filters than in unfiltered water, whereas water filtered through Waterdrop, WINGSOL, and MIST filters had higher levels of fluoride and calcium. Overall, the differences between filtered and unfiltered water were minor for fluoride (up to 4% reduction) but more substantial for calcium (up to 25% reduction). CLINICAL SIGNIFICANCE: The evaluated faucet-mounted water filters do not affect fluoride concentrations in tap water and thus the effectiveness of community water fluoridation in a clinically significant manner; however, some filters may reduce calcium concentrations significantly.