The answer to the question of how prevalent the coronavirus is in Gallatin County might come from an unlikely place — the sewer.

Researchers at Montana State University have been tracking the virus that causes COVID-19 through samples from Bozeman’s wastewater treatment plant on Springhill Road.

Between March 30, when the researchers began collecting samples, and April 6, they found the concentration of the virus in the wastewater generally declined, said Blake Wiedenheft, who is leading the research and is an associate professor in the MSU Department of Microbiology and Immunology in the College of Agriculture.

By April 8, the concentration of the virus was below detectable levels and has remained there since.