613COVID Website Update
Ottawa wastewater surveillance continues with testing and analysis performed in the lab of Dr. Robert Delatolla, Professor, Department of Civil Engineering, University of Ottawa, who has led that work since its inception in April 2020. The Delatolla lab has expanded its focus beyond SARS-CoV-2 to include influenza and RSV viruses.
Wastewater surveillance continues to be a key indicator to monitoring respiratory illnesses in Ottawa. We are honoured to have so many people in Ottawa use, consult, and support our application.
This monitoring program is currently funded by Ottawa Public Health and the Delatolla Research Group. Provincial funding for wastewater monitoring ended in July 2024. We are now fundraising to help support the continuation of this important community monitoring program.
Watch this space for our upcoming fundraising link!
Please see https://www.delatolla-research-group.ca for further information about the lab.
Wastewater plots last updated: 07 May, 2026, 16:47:18
Wastewater samples collected up to: 02 May, 2026
Reported date up to: 07 May, 2026
The website is updated on Wednesdays at approximately 5 p.m. Updates can be delayed if measurements do not pass quality assurance and quality control checks.
For mobile users, dragging the plot while in landscape mode will allow you to view current data. Using the display options at the top allows you to modify the view by zooming in and out of the plot.
Data last reported 2026-05-06. Click here for more details on wastewater data reporting.
Current growth estimates for the amount of virus in wastewater
| measure | estimate |
|---|---|
| Expected change in viral amount | Unsure |
| Rate of growth | 0.14 (0.01 – 0.33) |
| Doubling/halving time (days) | 5.1 (2.1 – 67) |
Influenza virus
Samples are screened for influenza A virus (IAV) once a week during the summer period (April to September). Samples are screened daily for IAV and influenza B virus (IBV) during the winter period (October to March). The website and plots are updated the day after processing.
The next plot illustrate the 7-day rolling mean in daily IAV wastewater viral signal. This number is the average of a week’s daily readings.
Respiratory Syncytial Virus Infection (RSV)
Samples are screened daily for respiratory syncytial virus (RSV) during the winter period (October to March). This test does not differentiate between RSV A and RSV B strains. The website and plots are updated the day after processing.
The next plots illustrate the 7-day rolling mean in daily RSV wastewater viral signal. This number is the average of a week’s daily readings. RSV is not a reportable disease, meaning that it does not fall under the list of diseases of public health significance in Ontario as designated by the Minister of Health\(^1\). Nevertheless, RSV has been identified as a disease that could benefit from wastewater-based surveillance given its contribution to seasonal emergency department visits and hospitalizations among young children and to outbreaks in healthcare institutions such as long-term care homes. Visit Respiratory Virus Detections in Canada for more information on RSV surveillance.
Interpretation cautions
The accuracy and reliability of SARS-CoV-2, influenza and RSV wastewater testing is improving as scientists understand the role of factors such as differences in sewage systems and laboratory protocols. Nonetheless, we recommend caution when interpreting daily or less then 3-day variation in the viral signal while evaluation of the methodology in public health surveillance is ongoing. Research is underway to arrive at a more precise estimate of sensitivity. For influenza and RSV, the level of detection is currently unknown as less than a year’s worth of data has been collected, but evaluation is ongoing. Thus, direct comparisons between wastewater signal levels for the 3 viruses is not recommended at this time. COVID-19, influenza and RSV wastewater signal is helpful when interpreted alongside other surveillance measures, taking into consideration the strengths and limitations of each measure. It is most promising as an early indicator\(^2\) of community viral activity and illness and may serve as a warning in advance of increased care-seeking, outbreaks and hospitalizations.
Visit the Ottawa Public Health Respiratory and Enteric Surveillance Report for more information on Ottawa’s public health surveillance of respiratory and enteric viruses.
For more information on wastewater testing in Ottawa, please see the contact page.
Citations:
Health Protection and Promotion Act, R.S.O. 1990, c. H.7. https://www.ontario.ca/laws/statute/90h07?search=diseases+of+public+health+significance.
Mercier, É. et al. Wastewater surveillance of influenza activity: Early detection, surveillance, and subtyping in city and neighbourhood communities (preprint). (2022) doi:10.1101/2022.06.28.22276884.
See the Methods page for more information on how the samples were collected, access to the data, and how the plots were created. The plots are currently for research only and presented to the public for discussion.
You can learn more about wastewater epidemiology and its role in COVID-19 surveillance on Ottawa Public Health’s website.
Definitions
* A 7-day average is generated by averaging the levels from a given day with the six previous days. The average is termed “rolling” as it changes each day.
* For new cases, the reported date is the day the test result is reported by the laboratory. Episode date is the approximate date of COVID-19 infection estimated from information available: the date of symptom onset, test date, or the reported date.
* Percent positivity refers to the percentage of individuals tested for either COVID-19 infection or influenza A infection in a given day that test positive.
* A central question in wastewater epidemiology is determining the proportion of the wastewater that is actually from humans and the proportion that is rain water, snow melt etc. To address this issue, viral copy data is thus normalized using a seasonally stable fecal biomarker; pepper mild mottle virus (PMMoV). See methods for more details.
^ Percent change in 7-day average is calculated by comparing the 7-day average (previous day 1 to 7) with a lagged 7-day average (days 8 to 14).
