Wastewater monitoring is used by scientists and public health officials to track the spread of diseases in communities. Since the 1960s, wastewater has been used to monitor for diseases such as polio through the analysis of human waste.

Measuring fragments of COVID‑19 virus in wastewater is a new science. These fragments are shed in the feces of an infected person a few days before, and up to three weeks after a person begins to feel ill. These fragments are not infectious.

Here’s how wastewater monitoring works:

  1. Wastewater samples are taken from a community location like a wastewater treatment plant or a high-risk facility like a retirement home.
  2. The wastewater samples are sent to labs and analyzed for the presence and spread of a disease by measuring specific targets such as concentration of virus fragments over time.
  3. The data is used by public health professionals to help them make decisions.

Monitoring wastewater gives a close to real-time way to track the spread of the COVID‑19 virus before people begin showing symptoms.

About the Wastewater Surveillance Initiative

In 2020, we established the Wastewater Surveillance Initiative to detect COVID‑19 in wastewater samples across Ontario.

As the COVID‑19 pandemic continues to evolve, and as our government looks ahead to ensure readiness for future health emergencies, we are investing an additional $24.7 million to:

  • sustain the Wastewater Surveillance Initiative
  • learn how wastewater surveillance could be used to detect other diseases of concern

The initiative uses wastewater sampling and clinical case and other public health data to:

  • help local public health units identify potential COVID‑19 outbreaks in their communities
  • enable more timely decisions about how and where to mobilize resources in response

Academic and research partners

We built on the work that was already underway in several communities in Ontario and partnered with academic and research institutions to create a provincial network that would ensure more public health units have access to wastewater data. The academic and research institution partners include:

  • Carleton University
  • University of Guelph
  • Health Sciences North Research Institute
  • McMaster University
  • Ontario Tech University
  • University of Ottawa
  • Queen’s University
  • Ryerson University
  • University of Toronto
  • Trent University
  • University of Waterloo
  • University of Western Ontario
  • University of Windsor

The Ontario Clean Water Agency (OCWA) is also providing technical expertise and equipment for testing in sampling locations.

Wastewater sampling locations

Wastewater sampling currently takes place in over 170 locations across the province, which covers over 75% of Ontario’s population.

Some examples of these locations include:

  • municipal wastewater treatment plants
  • long-term care facilities
  • university campuses
  • correctional facilities
  • hospitals
  • homeless shelters
  • retirement homes

The initial locations were chosen by participating municipalities, academic and research institutions and local public health units in consultation with Ontario Science Advisory Table members.

Additional locations were added in consultation with participating municipalities, academic and research institutions and local public health units.

Sampling and lab analysis guidance

Academic and research institutions are analyzing wastewater samples and producing reliable results for local public health units.

We developed a protocol document for analyzing wastewater samples. The protocol provides technical guidance to university and government lab scientists and commercial labs to help ensure quality assurance and control of sampling and analysis results.

Next steps

As the COVID‑19 pandemic in Ontario continues to evolve, we continue to use every tool available to monitor trends and detect outbreaks as early as possible. Wastewater surveillance can support Ontario’s re-opening and recovery by monitoring trends in wastewater, as well as the spread of Variants of Concern.

Data from the initiative will also continue to be an important tool to inform the province’s understanding of and response to the pandemic and could inform our response to future public health threats.