Testing wastewater to gauge community health isn't a new idea, but it took off during the COVID-19 pandemic. Viral levels in sewage could predict a rise in confirmed infections and associated increases in hospital visits.
"One of the things that we like to compare wastewater monitoring to is a weather report," explained Amanda Bidwell, the scientific program manager for WastewaterScan. "So you check your phone when you're going to go out for the day. Do you need to wear a jacket? Do you need an umbrella? Do you need scarves? Do you need a hat?"
WastewaterScan works with the cities of Boise and Coeur D'Alene, and dozens of other sites across the country. Data collected is shared with state and local health officials, according to Boise Public Works Spokesperson Abby Hardin.
While levels of COVID-19 are near zero in Boise wastewater these days, analysis tracks many different types of disease. Bidwell said Boise's is tested for 16 different viruses, with samples collected from both wastewater treatment sites and processed individually. The testing comes at no cost to the city; WastewaterScan is a grant-funded, academic project based at Stanford University in California.
"We look for respiratory viruses like COVID-19, influenza A and B and RSV. We also look at gastrointestinal pathogens like norovirus," she said. "And lastly, we look at emerging or rare pathogens like measles, West Nile virus, bird flu and hepatitis A."
Recently, researchers have seen an increase in rotavirus, which can cause severe illness in children. Viral levels are peaking across the country and in Idaho, Bidwell said June 3. Rotavirus is vaccine-preventable.
The number of municipalities participating with WastewaterScan has decreased since 2024. Bidwell said some cities or states established localized testing programs. Boise went the opposite way, joining the academic project in 2023. Hardin said the biggest difference was the way the data is compiled and displayed. Its own platform, which Boise stood up in 2021, required manual data entry and took a lot of staff time to publish.
Most wastewater testing programs across the country also feed into the National Wastewater Surveillance System, run by the Centers for Disease Control and Prevention. But WastewaterScan is the largest independent program doing this work, and generally tests for a wider range of pathogens than local programs, according to NWSS data.
"So right now we have funding through the end of 2026, but we are optimistic about the future of wastewater surveillance and wastewater scan over the next coming years," Bidwell said of the program's future.
But fewer people appear to be accessing the data on a regular basis. The City of Boise reported user traffic to its wastewater testing dashboard has declined as the COVID-19 pandemic continues to move further into the rear-view mirror. Dashboard visits still spike during cold and flu season.
"Even though site numbers may have changed, we have a really dedicated group of participants in this program who see the value in the data, not only for public health action, but for their communities," Bidwell said.
