No trace of COVID-19 has been found in wastewater tested in Rockland during the past two months.

Four tests have been conducted since May 6. The most recent test was done two weeks ago, showing no sign of the new virus.

One test indicated some of the virus but was later determined not to have been tested properly.

Wastewater Department Director Terry Pinto has cautioned previously that the type of testing is experimental.

This form of testing is being administered across the country.

The testing in Rockland was done by a group that include the Massachusetts Institute of Technology in Cambridge, Mass.; Harvard University in Cambridge; Brigham and Women's Hospital in Boston; and Biobot Analytics of Somerville, Mass. Since March 23, testing has been done pro bono by the group at 350 wastewater plants in more than 40 states across the United States.

The testing can detect genetic material in human feces.

There was no charge to the city for the earlier testing.

Pinto said, however, from now going on testing would cost $1,500 per test. He said he does not plan to have any additional testing done.