What samples are collected at the WWTPs participating in CDPH NWSS?
At each of the 13 WWTPs participating in CDPH NWSS, raw wastewater composite samples are collected three times a week at the headworks or influent of the treatment plant before the sewage gets treated.
How is SARS-CoV-2 measured from wastewater samples?
SARS-CoV-2 ribonucleic acid (RNA) or genetic material is detected and quantified from wastewater samples using a polymerase chain reaction (PCR) test.
Where can the results of the California NWSS sites be viewed?
Results from the California WWTPs participating in CDPH NWSS can be found on the
CDPH Wastewater Surveillance Network Dashboard.
Is SARS-CoV-2 in wastewater infectious?
To date, there are no scientific reports of the SARS-CoV-2 virus being transmitted to people through water in lakes, rivers, natural bodies of water, or wastewater.
Wastewater is processed (treated) before leaving a treatment plant, and studies have confirmed that viral RNA is not present in treated wastewater.
Operators and laboratory technicians at these facilities follow appropriate steps to reduce risk of exposure to all pathogens in raw sewage. For more information on wastewater operator safety, visit the
California State Water Resources Control Board webpage.
Can wastewater surveillance detect COVID-19 hotspots?
With wastewater surveillance for SARS-CoV-2, detecting COVID-19 hotspots within a sewershed is possible, mainly by testing upstream within a sewershed (i.e., testing subsewersheds). At this time, there is no routine monitoring at the subsewershed level in the CDPH NWSS project.
Can SARS-CoV-2 variants of concern be detected in wastewater?
SARS-CoV-2 variants of concern in wastewater can be detected. CDPH is working with academic and private laboratories to investigate methods to detect and monitor SARS-CoV-2 variants in wastewater.
How is the CDPH NWSS project funded?
CDPH NWSS is funded through a CDC Epidemiology and Laboratory Capacity (ELC) grant. Cost of sampling and analysis are currently being covered either by the participating sanitation district on a voluntary basis or partially by the CDC grant.