*Data generated in 2020 used a different method of concentrating wastewater samples and cannot be directly compared to data generated from January 2021 onward.
*For samples collected from February 25th, 2023 onward, BCCDC began using a more sensitive test for SARS-CoV-2 in wastewater. Increases in the viral signal after this date compared to before may be due in part to this change. Please use caution when comparing data before and after February 25th, 2023. Evidence of increased viral load of SARS-CoV-2 has been detected in the majority of reporting wastewater plants.
What Is the Chart Showing Me?
Each of the charts shows the amount of SARS-CoV-2 in wastewater, prior to treatment at one of Metro Vancouver's five wastewater treatment plants. Results are sorted by sewerage areas, which are defined catchment areas around each wastewater treatment plant. Wastewater from homes and businesses within each area is collected and directed to a specific wastewater treatment plant.
The charts show two types of data related to SARS-CoV-2:
- Concentration in Wastewater: Shows the amount of SARS-CoV-2 (copies/L) on the sample day.
- Concentration in Wastewater - Adjusted for Wastewater Flows: Shows the amount of SARS-CoV-2 (copies/day), which is the concentration of SARS-CoV-2 adjusted for the volume of wastewater entering the wastewater treatment plant on the day the sample was taken. This helps account for dilution from rain and stormwater that enters the wastewater system.
Metro Vancouver is measuring the amount of wastewater entering treatment plants to monitor how it affects SARS-CoV-2 concentrations in wastewater. To date, these additional data generally show similar trends to that of the raw data for SARS-CoV-2 in wastewater over time.
The science of COVID-19 is evolving rapidly. The data shown in the charts should be considered as general trends and not specific daily measurements. Note: In August 2021, wastewater testing for the SARS-CoV-2 increased to three times per week (previously once per week).
What the Chart Measurements Mean
The charts show SARS-CoV-2 concentrations in copies per litre or copies per day. Copies are a measure of the virus's genetic material, which gives an approximation of the amount of virus present in wastewater. If you click the "dynamic y axis" option, the scale on the y axis (vertical axis) will automatically adjust depending on the range of the data. This makes it easier to see values that may be very low or very high, which can be hard to accommodate within a single, static scale over the entire time period. Values can also be viewed by hovering over each bar.