Theresa Neubauer, 55, was found guilty on 11 counts of making false statements to a federal jury.
Neubauer concealed the use of a well from the government and citizens of Crestwood, a suburb of Chicago, to save money, prosecutors said, adding because of her actions, the village's leaking water system was not repaired and the water supply, normally drawn from Lake Michigan, was not properly monitored for contaminants for more than 20 years.
"Nobody really knows what was in the water for all those years because [Neubauer's] lies defeated testing," Assistant U.S. Attorney Timothy Chapman said in his closing statement.
A co-defendant, Frank Scaccia, 63, Crestwood's retired certified water operator, pleaded guilty this month to similar charges and is awaiting sentencing, a U.S. Department of Justice statement said.
Jessica Simpson shares three-way kiss with friends in photo
Scarlett Johansson steps out with fiance after pregnancy reveal