The California Department of Public Health (CDPH) is coordinating with wastewater utilities, local health departments, academic researchers, and laboratories in California on wastewater surveillance for infectious disease pathogens of interest to public health (such as SARS-CoV-2, the virus causing COVID-19, influenza, respiratory syncytial virus (RSV), mpox, and norovirus). Data collected from this network of participants, called the California Surveillance of Wastewaters (Cal-SuWers) Network, are submitted to the U.S. Centers for Disease Control and Prevention (CDC) National Wastewater Surveillance System (NWSS).

Collecting and analyzing wastewater samples for the presence of, and amount of (concentration), a specified pathogen target can help inform public health about circulation of that infectious disease within a community. Data from wastewater testing do not replace existing public health surveillance systems but complement them. While wastewater surveillance cannot determine the exact number of infected persons in the area being monitored, it can provide overall trends of pathogen concentration within that community.

Please note that data included in the Cal-SuWers Network and available here originate from multiple programs and laboratories. Methodologies for producing wastewater data are not currently standardized, and analyses, comparisons, and aggregations should be done with caution. Wastewater is a complex environmental sample and inherent variability in measured concentrations is expected due to environmental variability, day-to-day differences in sewershed and population dynamics, differences in the amount of shedding between people and pathogens, and laboratory and sampling variability. Please see the CDPH Cal-SuWers, CDC NWSS, and CDC Public Health interpretation and Use of Wastewater Surveillance data webpages for more information.

Historical wastewater data can be found here.