AbstractThis study focuses on using wastewater-based epidemiology to provide early warnings of the second COVID-19 wave in the Detroit metropolitan area of Michigan. SARS-CoV-2 RNA from untreated wastewater samples was compared to reported public health records. Untreated wastewater samples were collected from the Great Lakes Water Authority (GLWA) Water Resource Recovery Facility (WRRF), located in southeast Michigan, between August 6, 2020 and December 14, 2020. The WRRF receives wastewater from its service area via three main interceptors: the Detroit River Interceptor (DRI), the North Interceptor-East Arm (NIEA), and the Oakwood-Northwest-Wayne County Interceptor (ONWI). A total of 144 untreated wastewater samples were collected (45, 48, and 51 for ONWI, NIEA, and DRI, respectively) at the point of intake into the WRRF. Virus-selective sampling was conducted, and viruses were isolated from wastewater using electropositive NanoCeram column filters. For each sample, an average of 33 L of wastewater was passed through NanoCeram electropositive cartridge filters at an average rate of 11 L/min. Viruses were eluted and concentrated, and the SARS-CoV-2 RNA concentrations were quantified with RT-qPCR. SARS-CoV-2 RNA was detected in 98% of the samples, and measured concentrations were in the range of 4.45×104 to 5.30×106 genomic copies/L. Early warnings of COVID-19 peaks were observed approximately 4 weeks prior to reported publicly available clinical data.