On a Sunday morning in March 2020, right at the start of the pandemic, an article in Popular Mechanics caught engineer Pieter Van Ry’s eye. It had a catchy title: “How Poop Offers Hints About the Spread of Coronavirus.”

“At the end of that article, it said, ‘If you have a wastewater facility and you’re interested in participating in this study, please contact us,’” he said.

As a matter of fact, Van Ry did have a wastewater facility. He is the director of South Platte Renew, a wastewater treatment plant in Englewood, Colorado, that serves 300,000 people. He filled out the form, and South Platte joined the first facilities in the nation to start testing wastewater for covid-19.