Evaluation of drinking water quality test kits for home use in the United States

Water consumers in the United States may want to test their drinking water using at-home commercially available test kits rather than a certified laboratory due to convenience and affordability. However, while numerous do-it-yourself test kits are available for purchase online or at local stores, these kits are unregulated and lack data on their performance. We evaluated off-the-shelf home drinking water test kits that measure iron, copper, manganese, and fluoride concentrations to investigate whether these kits could reliably provide meaningful results. We evaluated their performance in three water matrices: deionized water (DI), tap water, and river water, and with laboratory-trained personnel compared to untrained users. Our results showed highly repeatable but variable performance in the test kits' ability to detect potential contaminants in the water. Most kits performed best in the DI water matrix with no interference. Our results suggest that there are concerns about their accuracy and usefulness and that whether the results can be relied on depends on which parameter is being measured in which water with which kit and for which purpose.