DENVER (KDVR) — If Coloradans’ sewage is any indication, the omicron wave might be on the downswing.

Most of the state’s largest metro areas have wastewater testing facilities that measure the presence of COVID-19. Because testing wastewater can detect asymptomatic cases, it can offer a broader picture of how prevalent the virus really is in a given community.

Wastewater treatment facilities for Aurora, Boulder and Denver each show large spikes in the amount of COVID-19 in wastewater that peaked on Jan. 6. This was also the day when Colorado’s daily cases hit their highest-ever point.

Since then, wastewater samples have shown less and less COVID at these five treatment facilities. On average, these five facilities had roughly 40% less COVID in their wastewater on Jan. 13 than they did on Jan. 6.

Similar wastewater readings have signaled a plateau in COVID cases in Boston, New York City and elsewhere along the East Coast.

Other cities, however, have not had the same readings. Colorado Springs, Pueblo and Broomfield’s wastewater readings have gone up in the last week.