Impact of corrosive groundwater on water infrastructure and public health in the contiguous United States.

In U.S. drinking water systems, corrosion in aging iron (Fe) and lead (Pb) pipes imposes significant economic challenges, damages infrastructure, and presents public health risks. Despite these issues, large-scale detection of pipe corrosion remains difficult. Previous studies established that corrosivity of supplied water is the critical contributor to pipe corrosion. Groundwater is the primary source of drinking water supply in the U.S., therefore, this study systematically investigated the spatiotemporal characteristics of groundwater corrosivity across the contiguous U.S and quantified its impacts. Findings indicate that groundwater corrosivity increased at 59% and 57% of monitoring sites over the past 50 years for Fe- and Pb-related corrosivity, respectively. To fill the spatial gaps of clustered monitoring data, we developed random forest models to predict regions with high Fe- and Pb-corrosivity of groundwater at 1-km resolution across the contiguous U.S., revealing that around one-third of the area is covered with corrosive groundwater. By quantifying its impact on water infrastructure and public health at national, state, and public water system levels, we estimated that approximately 5.72% -11.03% of total pipe length is at risk of Fe corrosion and 6.49 -7.79 million individuals face health risks from Pb corrosion. Finally, the study offered informative insights for monitoring focuses of the water supply systems. Overall, this study addresses deficiencies in groundwater monitoring, highlights the necessity of identifying high-risk areas for pipe corrosion, and contributes to the enhancement of monitoring systems and water supply infrastructure.