Identifying impacts and causes of drinking water quality issues through community-based participatory research in a suburban neighborhood in Texas: The case of Austin’s Colony

Growing water scarcity is driving many drinking water suppliers to mix water from different sources, increasing risks of pH-, redox-, and mineral-equilibrium water quality issues. Residents of Austin’s Colony (central Texas) have received hard water and intermittent discolored water for over a decade and face high water rates, bottled water costs, and appliance maintenance costs. Supply comes from a local shallow alluvial aquifer and a deeper sandstone aquifer 85 km away. We used Community-Based Participatory Research (CBPR), involving academics, residents, and community organization staff, to investigate the extent and causes of water issues in Austin’s Colony. We conducted community meetings, surveys ( n = 100), and bacterial and chemical analyses (cations, anions, Sr isotopes) of tap water samples ( n = 78). CBPR was essential for defining objectives, recruiting participants, and water sampling. Most survey participants (70%) reported discolored water events, and only 7% drink untreated tap water. Al, Mn, Fe, Cu, and Pb concentrations exceed regulatory limits in water samples, but were below regulatory standards in in-home treated samples. Geochemical analysis shows that the water composition at each household varies based on mixing between two or three groundwater sources, with the alluvial aquifer providing most of Ca and Mg driving hardness. Through mixing models and spatial analysis, we link household water quality to spatial location within the distribution network and identify groundwater mixing as the principal control on water quality. Mixing may also drive water quality changes associated with corrosion and mineral precipitation within the network, which, along with water turbulence, may explain discoloration events. Increased use of the Carrizo-Wilcox aquifer will likely reduce hardness and discoloration. This high-spatial-resolution geochemical mixing approach can inform water management in other distribution networks that mix different water sources. We highlight the importance of monitoring household water quality and evaluating practices to address water scarcity in rapidly growing areas.