https://www.wcvb.com/article/boston-area-sewage-study-finds-surge-in-indicators-of-covid-19-infections/34510204

CHELSEA, Mass. — Samples of sewage taken from a treatment plant that serves the Boston region reveals a dramatic increase in the presence of COVID-19 in the community over the course of October.

Wastewater samples are taken multiple times each week at the Deer Island Treatment Plant and analyzed by the Massachusetts Water Resources Authority’s contracted laboratory, Biobot Analytics. The lab looks for viral RNA in the sewage samples and returns results in copies per milliliter.

Samples taken Monday returned a measurement of 120 copies per milliliter from both the MWRA's northern and southern regions. For the southern region, it was the 11th consecutive sample with more than 100 copies per milliliter.