Top state House officials are reviewing the procedures and options for impeachment.
Darr, a Republican, acknowledged to the Ethics Commission last week that he broke state ethics and campaign laws 11 times since 2010 and agreed to pay $11,000 in fines.
Darr refused Tuesday to step down over the violations, which he says weren't intentional. He also said he didn't believe there was a public outcry for him to quit.
The top Republican in the House said he believed the chamber would impeach the lieutenant governor if he doesn't step down.