Assessing Water Filtration and Purification Practices and Their Impact on Tap Water Mineral Levels in Jeddah City

This study investigated the prevalence of water filtration and purification systems [WFPSs] in Jeddah, Saudi Arabia, and the impact of WFPSs on mineral concentrations in tap water. A convenience sample of residents completed a questionnaire on water usage/sources and provided water samples. Water was analyzed [fluoride—ion-specific electrode; metals—atomic absorption spectrometry]. Nonparametric testing was performed to compare mineral concentrations between different water sources, and questionnaire associations underwent correlation tests. Ninety-nine participants completed the study. Sixty percent reported using some type of WFPS. The most used WFPSs were reverse osmosis [RO] systems [62%], followed by whole-house carbon filters [8%] and faucet-mounted filters [6%]. Fluoride concentrations were very low across all WFPSs [all median; RO—0.02 ppm, other WFPS—0.01 to 0.05 ppm] and in unfiltered tap water [0.02 ppm]. RO systems reduced the concentrations of several minerals [magnesium—1.40 ppm, p = 0.006; potassium—0.55 ppm, p = 0.016; sodium—7.88 ppm, p = 0.001] compared to those in unfiltered tap water [magnesium—1.8 ppm; potassium—0.62 ppm; sodium—10.60 ppm]. However, RO systems did not affect calcium concentrations [10.93 ppm] compared to those in unfiltered tap water [11.47 ppm]. Participants with larger households were significantly more likely to use tap water treatment systems [p = 0.002]. The observed reduction in certain mineral concentrations raises concerns about potential nutritional implications.