Officials are asking Wellesley residents to boil their water before use due to positive testing for E. coli and other bacteria in “at least one’’ of the town’s resevoirs.

Users are asked to boil water for at least one minute before any human consumption, or use bottled water as an alternate source.

Ria Convery, spokeswoman for the Massachusetts Water Resources Authority, told The Boston Globe that the risk didn’t appear high, but that it was “better to err on the side of caution.’’

The advisory is not expected to last long, though no exact estimates are available.