While overall cases of the viral COVID-19 are down, it is still critically important to keep track of when and where the disease might be reemerging, especially as new variants spread and potentially trigger new surges of infections. Monitoring of COVID-19 breakouts has been made more effective by advances in wastewater testing led by researchers such as Fulton Schools Professor Rolf Halden, director of ASU Biodesign Center for Environmental Health Engineering. During the height of the COVID-19 pandemic, Halden’s wastewater testing in Tempe and surrounding areas led to identifying a previously undocumented virus hotspot in the neighboring town of Guadalupe, home to a large number of Native American and Latino residents who often did not have access to COVID-19  tests. Halden and others are still working to improve the effectiveness of their techniques, and experts expect this kind of testing to remain important for the detection and monitoring of any future pandemics.