Wastewater Surveillance for COVID-19


The virus (and its variants) that causes COVID-19 (SARS-CoV-2) can be detected in the stool of infected people.  Testing and monitoring wastewater (sewage) for the presence of SARS-CoV-2 provides an opportunity to detect the presence of COVID-19 infections in a community without having to collect and test samples from individuals.  Regularly testing wastewater for COVID-19 is a population level intervention that can serve as an early warning system for COVID-19 resurgence because the virus is often detected in sewage before individual cases are detected by traditional surveillance (i.e., positive individual COVID-19 test results).

PEI’s Chief Public Health Office and the Department of Environment, Energy and Climate Action have partnered with the municipalities of Alberton, Charlottetown, Montague, Souris, Stratford, and Summerside and the National Microbiology Laboratory in Winnipeg to implement wastewater surveillance for COVID-19 in PEI.  

Samples are collected from the wastewater treatment plants by utility staff and all samples are shipped to the National Microbiology Laboratory for analysis. 

Interpreting Wastewater Data

Visit the COVID-19 wastewater surveillance dashboard website for more information.

(for more information, see https://health-infobase.canada.ca/covid-19/wastewater/technical-notes.html)

  • “Viral load” is the amount of SARS-CoV-2 genetic material present in a sample of wastewater.  
  • “Copies per mL” is the number of copies of the target SARS-CoV-2 gene found in one milliliter (mL) of wastewater.

The viral load in a wastewater sample is affected by the composition of the wastewater, which varies by community.   Variables such as ground or surface water, industrial flow into the wastewater system, and temperature can impact the viral load.  For these reasons, viral load is not comparable between communities.  

Use caution when interpreting daily and short-term changes in viral load, as the wastewater signal can change from day to day. An ongoing increase or decrease across numerous samples (i.e., weeks) in the viral load is more reliable for indicating trends.

Wastewater Surveillance Results

PEI wastewater testing results are now included on the national COVID-19 wastewater surveillance dashboard (link is external) 


Published date: 
December 20, 2022
Health and Wellness

General Inquiries

Department of Health and Wellness
4th Floor North, Shaw Building
105 Rochford Street
Charlottetown, PE   C1A 7N8

Phone: 902-368-6414
Fax: 902-368-4121