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Testing for the COVID-19 Virus in Wastewater


Metro Vancouver is working with the B.C. Centre for Disease Control (BCCDC) and the University of British Columbia to track the presence of SARS-CoV-2 (the virus that causes COVID-19), in the region’s wastewater​. More comprehensive data, including trends analysis, is available through the BC Centre for Disease Control. SARS-CoV-2 is shed in the feces of people with COVID-19 and can be detected in wastewater. 

Untreated wastewater is sampled and tested for the virus three times a week.

What wastewater testing can (and can’t) tell us

Testing wastewater can tell us if the SARS-CoV-2 is present and how it might be changing over time. This information may help health authorities evaluate the effectiveness of measures to control the virus in the community. Wastewater testing cannot tell us the number of people that are infected or contagious. COVID-19 case information is available through the BC Centre for Disease Control.​

Results posting schedule

Metro Vancouver collects wastewater samples and sends them to the ​​BC Centre for Disease Control for testing. Results are posted to our website as soon as we receive them from the BC Centre for Disease Control. Results are posted to our website as soon as we receive them from the BC Centre for Disease Control.

On February 28, 2023 the BC Centre for Disease Control began using a new test to determine the amount of SARS-COV-2 in wastewater. This new test is more sensitive and able to detect more viral particles in a wastewater sample. The BC Centre for Disease Control has used this new test to retest archived wastewater samples dating back to the fall of 2021. This provides consistent results and charts have been updated using the results of the new test, from fall of 2021 onwards.

Values from the new test are not directly comparable to values from the old test. However, trends over time and associated conclusions remain similar between the old and new test results.

 Graphs showing the results of the old test from September 28, 2020 – September 22, 2021


*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.

​Understanding information shown on the chart​

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.

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