The use of unsafe water as a source for drinking, cooking, and bathing can lead to serious health complications. Point of Use (POU) water treatment technologies can play an important role in making safe and clean drinking water available to communities. One low-cost, low-technology POU system is the biosand filter (BSF). BSFs offer an effective household-level treatment that is being used in developing countries. BSFs have three layers of media: a coarse gravel underdrain at the bottom, a separation layer of finer gravel, and sand as the main filter medium. The article examines an activity for experimenting with BSFs as a way for students to participate in solving the problem of water scarcity, poor water quality, and inadequate sanitation that have negatively impacted the health and livelihoods for families around the world. This activity is best begun by providing students with background information about the need for POU water treatment, including content such as the amount of fresh water available for human use, why there are shortages in particular places, and how water gets contaminated. A focus on the shortage of potable water and the use of BSFs to respond to this problem opens up a wide range of other science content (disciplinary core ideas) that can be addressed as the students engage in the science and engineering practices (SEPs). Topics such as adsorption, filtration, and biodegradation as the water flows through the BSF; the need for enough hydraulic head to cause the water to move through the BSF; and the biological processes that results in the growth of the biolayer and how beneficial microbes compete with pathogens could all be addressed.