COVID-19 has been detected in samples of wastewater taken from sewers on the University of Idaho campus, according to a UI research team.

Wastewater samples from eight specific on-campus living areas were collected and analyzed last week by researchers with assistance from facilities staff.

Results from the study indicate that two of the eight residence areas show evidence of the virus. Students who live in those areas were notified of the results over the weekend and will be tested for COVID-19 this week.

Thibault Stalder, from the UI Department of Biological Sciences and a member of the research team, says wastewater testing has advantages over clinical-based swab testing.

“Clinical-based testing fails to detect early warning of an outbreak because when the virus is detected in a community, it’s already been spread through the community — it will be difficult to contain the outbreak,” Stalder said in an online presentation he gave about his research Tuesday. “Wastewater-based testing can detect the virus in the population before clinical-based testing, providing a good estimate of the prevalence in the population.”

The ability to predict an outbreak allows people in areas which pose a high risk of infection to take precautions and get tested early on.

Wastewater testing also poses economic advantages when compared to clinical-based testing, according to Stalder.

“It’s cost-effective, because just by sampling a single area every day, you can get a general overview of the spread of the virus into the population of that area,” he said

Stalder and his team plan to test campus wastewater twice a week and report results to the university. Their analysis will focus on finding geographic areas where the virus can be detected, not on estimating infection rates — something outside the scope of their current modeling capabilities.

Ellen Dennis can be reached at (208) 883-4632 or by email at

Recommended for you