The Bangor Wastewater Treatment Plant, which cleans 8 million to 9 million gallons of water each day, is pictured on Jan. 5, 2016. Credit: Gabor Degre / BDN

Several major Maine cities and towns saw COVID-19 concentrations in wastewater that were among the highest in the nation in the past week, with most counties seeing big increases.

The state’s top public health official warned last week that wastewater data showed the virus was back on the rise here. Reported COVID-19 infections have also surged this week, with the more contagious version of the omicron variant accounting for most new cases.

The concentration of the virus in the wastewater in sites across Maine is still lower than when the state began regularly testing wastewater in late January, amid the first omicron surge, according to data from the Maine Center for Disease Control and Prevention and Biobot. But the sharp rise in virus concentration in the wastewater could indicate a surge in cases that Maine may not be fully capturing due to greater use of at-home testing. 

Significant jumps at several wastewater testing sites in the state in the past week put them among the worst when compared to U.S. sites using the same detection method right now. Since April 7, wastewater testing sites in Bangor, Belfast, Brunswick, Calais, Fort Kent, Houlton, Machias, Lewiston and Westbrook have reported wastewater with virus concentrations in the highest 10 percent nationally.

Virus concentrations remain lower at other sites in the state, but most have still ticked upward compared to a few weeks ago.

Reported COVID-19 cases in Maine have also jumped 50 percent in the past week, with the seven-day average rising to 316 daily cases on Friday, up from 211 a week prior. Cases have also risen nationwide in the past week, according to the New York Times, but not as rapidly.

Hospitalizations in Maine have not yet seen a similar surge. As of Friday, 101 people were hospitalized with the virus in Maine, with 18 in critical care beds and four on ventilators.