Dittmar will replace Sara Bristol who resigned from the District two seat. He will serve the remaining two years of Bristol's term.
Dittmar is an investigator with the state's Department of Labor and Industries. He said he looks forward to joining council.
"My number one goal for the council is to be a good council member and help the council come to the decisions that will benefit the citizens," said Thomas Dittmar.
Dittmar will be sworn in before Tuesday evening's council meeting.