Pemsl, a 22-year-old junior, is facing a charge of operating while intoxicated in Iowa City, Iowa.
Iowa City authorities said in a court filing that Pemsl had bloodshot eyes, failed a field sobriety test and registered a blood alcohol content of .151 on a breath test when he was pulled over at around 3 a.m. The legal limit to drive is .08.
The athletics department said in a statement that it is still gathering facts in the case.
A public defender has been appointed to represent Pemsl. The public defender's office didn't immediately reply to a message seeking comment.
In May, the Big Ten granted Pemsl a waiver after he played only 29 minutes last season because of complications involving hardware from a knee surgery he had in high school. The waiver meant Pemsl has two remaining years of eligibility.
Pemsl has averaged 7.2 points and 4.7 rebounds per game through two-plus seasons for the Hawkeyes.
The Associated Press contributed to this report.