AMHERST - A water sample taken Wednesday in North Amherst tested positive for disease-causing E. coli bacteria, said Robert Pariseau, director of water resources.

In addition, one sample taken on the University of Massachusetts campus and another taken near the campus tested positive for total coliform, he said. Coliform is not dangerous but is an indicator of problems with the water system, he said.

A total of 10 samples at and near the sites of the previous contamination will be taken today, the results of which will be available around noon Saturday, Pariseau said. One positive test would trigger an order to boil water in the area of the sample, and more than one would bring a townwide boil order, he said.

The heavy rain this summer could be a factor in the positive tests, which have occurred in other towns as well, Pariseau said. He said he could not explain the positive E. coli, because the sample showed high enough chlorine levels to kill bacteria.

There has never been a positive test for E. coli in Amherst before, he said.

Check gazettenet.com after noon Saturday for results of the retesting.

Nick Grabbe can be reached at ngrabbe@gazettenet.com.