The belief is the viral load in wastewater is a precursor to a surge in cases and symptoms in the region.
The Massachusetts Water Resource Authority reported a seven-day rolling average of 130 copies of viral load per milliliter for southern areas of the water authority zone and 178 copies for areas north of Boston, with a daily high of 271 copies on Wednesday in the north and 263 in the south on Oct. 18.
Those numbers represent the highest levels measured since a daily measurement of 345 in the south April 21.
The highest measured levels of the pandemic were 361 in the north on April 8 and 366 in the south on April 6. The highest seven-day average was 312 in the south region on April 21.
Rates reached a low of eight copies in the north three times in June — most recently on June 27, and six copies in the south on June 22.
The water authority notes this is a pilot program of an evolving science. The results from this study are used by public health officials as an additional tool for the commonwealth to track how the pandemic is trending in Massachusetts, along with data from clinical tests, hospitalizations and other metrics.
The data, taken together, is used by state officials to make decisions about how to quickly respond, according to water authority.
The measurements coincide with a rise in coronavirus cases statewide in recent weeks.